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proofwiki-7900
Bisection of Angle in Cartesian Plane
Let $\theta$ be the angular coordinate of a point $P$ in a polar coordinate plane. Let $QOR$ be a straight line that bisects the angle $\theta$. Then the angular coordinates of $Q$ and $R$ are $\dfrac \theta 2$ and $\pi + \dfrac \theta 2$.
:500px Let $A$ be a point on the polar axis. By definition of bisection, $\angle AOQ = \dfrac \theta 2$. This is the angular coordinate of $Q$. {{qed|lemma}} Consider the conjugate angle $\map \complement {\angle AOP}$ of $\angle AOP$. By definition of conjugate angle: :$\map \complement {\angle AOP} = -2 \pi - \theta$...
Let $\theta$ be the [[Definition:Angular Coordinate|angular coordinate]] of a [[Definition:Point|point]] $P$ in a [[Definition:Polar Coordinate Plane|polar coordinate plane]]. Let $QOR$ be a [[Definition:Straight Line|straight line]] that [[Definition:Bisection|bisects]] the [[Definition:Angle|angle]] $\theta$. Then...
:[[File:BisectedAngle.png|500px]] Let $A$ be a [[Definition:Point|point]] on the [[Definition:Polar Axis (Polar Coordinates)|polar axis]]. By definition of [[Definition:Bisection|bisection]], $\angle AOQ = \dfrac \theta 2$. This is the [[Definition:Angular Coordinate|angular coordinate]] of $Q$. {{qed|lemma}} Con...
Bisection of Angle in Cartesian Plane
https://proofwiki.org/wiki/Bisection_of_Angle_in_Cartesian_Plane
https://proofwiki.org/wiki/Bisection_of_Angle_in_Cartesian_Plane
[ "Analytic Geometry" ]
[ "Definition:Polar Coordinates/Angular Coordinate", "Definition:Point", "Definition:Polar Coordinates/Polar Plane", "Definition:Line/Straight Line", "Definition:Bisection", "Definition:Angle", "Definition:Polar Coordinates/Angular Coordinate" ]
[ "File:BisectedAngle.png", "Definition:Point", "Definition:Polar Coordinates/Polar Axis", "Definition:Bisection", "Definition:Polar Coordinates/Angular Coordinate", "Definition:Conjugate Angles", "Definition:Conjugate Angles", "Definition:Clockwise", "Definition:Angle", "Definition:Polar Coordinate...
proofwiki-7901
Sine of 15 Degrees
:$\sin 15 \degrees = \sin \dfrac \pi {12} = \dfrac {\sqrt 6 - \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \sin 15 \degrees | r = \sin \frac {30 \degrees} 2 | c = }} {{eqn | r = \sqrt {\frac {1 - \cos 30 \degrees} 2} | c = Half Angle Formula for Sine: $\theta$ is in Quadrant I }} {{eqn | r = \sqrt {\frac {1 - \frac {\sqrt 3} 2} 2} | c = {{cos|30}} }} {{eqn | r = \sqrt {\fra...
:$\sin 15 \degrees = \sin \dfrac \pi {12} = \dfrac {\sqrt 6 - \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \sin 15 \degrees | r = \sin \frac {30 \degrees} 2 | c = }} {{eqn | r = \sqrt {\frac {1 - \cos 30 \degrees} 2} | c = [[Half Angle Formula for Sine]]: $\theta$ is in [[Definition:Sine/Definition from Circle/First Quadrant|Quadrant I]] }} {{eqn | r = \sqrt {\frac {1 - \frac {\s...
Sine of 15 Degrees/Proof 1
https://proofwiki.org/wiki/Sine_of_15_Degrees
https://proofwiki.org/wiki/Sine_of_15_Degrees/Proof_1
[ "Sine Function", "Sine of 15 Degrees" ]
[]
[ "Half Angle Formulas/Sine", "Definition:Sine/Definition from Circle/First Quadrant", "Definition:Sine/Definition from Circle/First Quadrant" ]
proofwiki-7902
Sine of 15 Degrees
:$\sin 15 \degrees = \sin \dfrac \pi {12} = \dfrac {\sqrt 6 - \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \sin 15 \degrees | r = \map \sin {45 \degrees - 30 \degrees} | c = }} {{eqn | r = \sin 45 \degrees \cos 30 \degrees - \cos 45 \degrees \sin 30 \degrees | c = Sine of Difference }} {{eqn | r = \paren {\frac {\sqrt 2} 2} \paren {\frac {\sqrt 3} 2} - \paren {\frac {\sqrt 2} 2} ...
:$\sin 15 \degrees = \sin \dfrac \pi {12} = \dfrac {\sqrt 6 - \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \sin 15 \degrees | r = \map \sin {45 \degrees - 30 \degrees} | c = }} {{eqn | r = \sin 45 \degrees \cos 30 \degrees - \cos 45 \degrees \sin 30 \degrees | c = [[Sine of Difference]] }} {{eqn | r = \paren {\frac {\sqrt 2} 2} \paren {\frac {\sqrt 3} 2} - \paren {\frac {\sqrt 2}...
Sine of 15 Degrees/Proof 2
https://proofwiki.org/wiki/Sine_of_15_Degrees
https://proofwiki.org/wiki/Sine_of_15_Degrees/Proof_2
[ "Sine Function", "Sine of 15 Degrees" ]
[]
[ "Sine of Difference", "Sine of 45 Degrees", "Cosine of 30 Degrees", "Cosine of 45 Degrees", "Sine of 30 Degrees" ]
proofwiki-7903
Sine of 30 Degrees
:$\sin 30 \degrees = \sin \dfrac \pi 6 = \dfrac 1 2$
:200px Let $\triangle ABC$ be an equilateral triangle of side $r$. By definition, each angle of $\triangle ABC$ is equal. From Sum of Angles of Triangle equals Two Right Angles it follows that each angle measures $60^\circ$. Let $CD$ be a perpendicular dropped from $C$ to $AB$ at $D$. Then $AD = \dfrac r 2$ while: :$\a...
:$\sin 30 \degrees = \sin \dfrac \pi 6 = \dfrac 1 2$
:[[File:Sine30.png|200px]] Let $\triangle ABC$ be an [[Definition:Equilateral Triangle|equilateral triangle]] of [[Definition:Side of Polygon|side]] $r$. By definition, each [[Definition:Angle|angle]] of $\triangle ABC$ is equal. From [[Sum of Angles of Triangle equals Two Right Angles]] it follows that each [[Defin...
Sine of 30 Degrees
https://proofwiki.org/wiki/Sine_of_30_Degrees
https://proofwiki.org/wiki/Sine_of_30_Degrees
[ "Sine Function" ]
[]
[ "File:Sine30.png", "Definition:Triangle (Geometry)/Equilateral", "Definition:Polygon/Side", "Definition:Angle", "Sum of Angles of Triangle equals Two Right Angles", "Definition:Angle", "Definition:Right Angle/Perpendicular", "Definition:Sine" ]
proofwiki-7904
Sine of 45 Degrees
:$\sin 45 \degrees = \sin \dfrac \pi 4 = \dfrac {\sqrt 2} 2$
:300px Let $ABCD$ be a square of side $r$. By definition, each angle of $\triangle ABCD$ is equal to $90 \degrees$. Let $AC$ be a diagonal of $ABCD$. As $\triangle ABC$ is a right angled triangle, it follows from Pythagoras's Theorem that $AC = \sqrt 2 A B$. As $AC$ is a bisector of $\angle DAB$ it follows that $\angle...
:$\sin 45 \degrees = \sin \dfrac \pi 4 = \dfrac {\sqrt 2} 2$
:[[File:Sine45.png|300px]] Let $ABCD$ be a [[Definition:Square (Geometry)|square]] of [[Definition:Side of Polygon|side]] $r$. By definition, each [[Definition:Angle|angle]] of $\triangle ABCD$ is equal to $90 \degrees$. Let $AC$ be a [[Definition:Diagonal of Quadrilateral|diagonal]] of $ABCD$. As $\triangle ABC$ i...
Sine of 45 Degrees/Proof 1
https://proofwiki.org/wiki/Sine_of_45_Degrees
https://proofwiki.org/wiki/Sine_of_45_Degrees/Proof_1
[ "Sine of 45 Degrees", "Sine Function" ]
[]
[ "File:Sine45.png", "Definition:Quadrilateral/Square", "Definition:Polygon/Side", "Definition:Angle", "Definition:Diameter of Quadrilateral", "Definition:Triangle (Geometry)/Right-Angled", "Pythagoras's Theorem", "Definition:Bisection", "Definition:Sine" ]
proofwiki-7905
Sine of 45 Degrees
:$\sin 45 \degrees = \sin \dfrac \pi 4 = \dfrac {\sqrt 2} 2$
{{begin-eqn}} {{eqn | l = \sin 45 \degrees | r = \map \sin {30 \degrees + 15 \degrees} | c = }} {{eqn | r = \sin 30 \degrees \cos 15 \degrees + \cos 30 \degrees \sin 15 \degrees | c = Sine of Sum }} {{eqn | r = \paren {\frac 1 2} \paren {\frac {\sqrt 6 + \sqrt 2} 4} + \paren {\frac {\sqrt 3} 2} \pare...
:$\sin 45 \degrees = \sin \dfrac \pi 4 = \dfrac {\sqrt 2} 2$
{{begin-eqn}} {{eqn | l = \sin 45 \degrees | r = \map \sin {30 \degrees + 15 \degrees} | c = }} {{eqn | r = \sin 30 \degrees \cos 15 \degrees + \cos 30 \degrees \sin 15 \degrees | c = [[Sine of Sum]] }} {{eqn | r = \paren {\frac 1 2} \paren {\frac {\sqrt 6 + \sqrt 2} 4} + \paren {\frac {\sqrt 3} 2} \...
Sine of 45 Degrees/Proof 2
https://proofwiki.org/wiki/Sine_of_45_Degrees
https://proofwiki.org/wiki/Sine_of_45_Degrees/Proof_2
[ "Sine of 45 Degrees", "Sine Function" ]
[]
[ "Sine of Sum" ]
proofwiki-7906
Sine of 45 Degrees
:$\sin 45 \degrees = \sin \dfrac \pi 4 = \dfrac {\sqrt 2} 2$
{{begin-eqn}} {{eqn | l = \sin 45 \degrees | r = \map \sin {3 \times 15 \degrees} | c = }} {{eqn | r = 3 \sin 15 \degrees - 4 \sin^3 15 \degrees | c = Triple Angle Formula for Sine }} {{eqn | r = 3 \paren {\frac {\sqrt 6 - \sqrt 2} 4} - 4 \paren {\frac {\sqrt 6 - \sqrt 2} 4}^3 | c = {{sin|15}} ...
:$\sin 45 \degrees = \sin \dfrac \pi 4 = \dfrac {\sqrt 2} 2$
{{begin-eqn}} {{eqn | l = \sin 45 \degrees | r = \map \sin {3 \times 15 \degrees} | c = }} {{eqn | r = 3 \sin 15 \degrees - 4 \sin^3 15 \degrees | c = [[Triple Angle Formula for Sine]] }} {{eqn | r = 3 \paren {\frac {\sqrt 6 - \sqrt 2} 4} - 4 \paren {\frac {\sqrt 6 - \sqrt 2} 4}^3 | c = {{sin|1...
Sine of 45 Degrees/Proof 3
https://proofwiki.org/wiki/Sine_of_45_Degrees
https://proofwiki.org/wiki/Sine_of_45_Degrees/Proof_3
[ "Sine of 45 Degrees", "Sine Function" ]
[]
[ "Triple Angle Formulas/Sine" ]
proofwiki-7907
Sine of 45 Degrees
:$\sin 45 \degrees = \sin \dfrac \pi 4 = \dfrac {\sqrt 2} 2$
{{begin-eqn}} {{eqn | l = \sin 45 \degrees | r = \map \sin {60 \degrees - 15 \degrees} }} {{eqn | r = \sin 60 \degrees \cos 15 \degrees - \cos 60 \degrees \sin 15 \degrees | c = Sine of Difference }} {{eqn | r = \paren {\frac {\sqrt 3} 2} \paren {\frac {\sqrt 6 + \sqrt 2} 4} - \paren {\frac 1 2} \paren {\fr...
:$\sin 45 \degrees = \sin \dfrac \pi 4 = \dfrac {\sqrt 2} 2$
{{begin-eqn}} {{eqn | l = \sin 45 \degrees | r = \map \sin {60 \degrees - 15 \degrees} }} {{eqn | r = \sin 60 \degrees \cos 15 \degrees - \cos 60 \degrees \sin 15 \degrees | c = [[Sine of Difference]] }} {{eqn | r = \paren {\frac {\sqrt 3} 2} \paren {\frac {\sqrt 6 + \sqrt 2} 4} - \paren {\frac 1 2} \paren ...
Sine of 45 Degrees/Proof 4
https://proofwiki.org/wiki/Sine_of_45_Degrees
https://proofwiki.org/wiki/Sine_of_45_Degrees/Proof_4
[ "Sine of 45 Degrees", "Sine Function" ]
[]
[ "Sine of Difference", "Sine of 60 Degrees", "Cosine of 15 Degrees", "Cosine of 60 Degrees", "Sine of 15 Degrees" ]
proofwiki-7908
Sine of 45 Degrees
:$\sin 45 \degrees = \sin \dfrac \pi 4 = \dfrac {\sqrt 2} 2$
{{begin-eqn}} {{eqn | l = \sin 90 \degrees | r = 1 | c = Sine of Right Angle }} {{eqn | ll= \leadsto | l = \map \sin {2 \times 45 \degrees} | r = 1 | c = }} {{eqn | ll= \leadsto | l = 2 \sin 45 \degrees \cos 45 \degrees | r = 1 | c = Double Angle Formula for Sine }} {{eq...
:$\sin 45 \degrees = \sin \dfrac \pi 4 = \dfrac {\sqrt 2} 2$
{{begin-eqn}} {{eqn | l = \sin 90 \degrees | r = 1 | c = [[Sine of Right Angle]] }} {{eqn | ll= \leadsto | l = \map \sin {2 \times 45 \degrees} | r = 1 | c = }} {{eqn | ll= \leadsto | l = 2 \sin 45 \degrees \cos 45 \degrees | r = 1 | c = [[Double Angle Formula for Sine]]...
Sine of 45 Degrees/Proof 5
https://proofwiki.org/wiki/Sine_of_45_Degrees
https://proofwiki.org/wiki/Sine_of_45_Degrees/Proof_5
[ "Sine of 45 Degrees", "Sine Function" ]
[]
[ "Sine of Right Angle", "Double Angle Formulas/Sine", "Sine of Complement equals Cosine", "Definition:Acute Angle", "Definition:Sine/Definition from Circle/First Quadrant" ]
proofwiki-7909
Sine of 60 Degrees
:$\sin 60 \degrees = \sin \dfrac \pi 3 = \dfrac {\sqrt 3} 2$
{{begin-eqn}} {{eqn | l = \sin 60 \degrees | r = \map \cos {90 \degrees - 60 \degrees} | c = Cosine of Complement equals Sine }} {{eqn | r = \cos 30 \degrees | c = }} {{eqn | r = \dfrac {\sqrt 3} 2 | c = Cosine of $30 \degrees$ }} {{end-eqn}} {{qed}}
:$\sin 60 \degrees = \sin \dfrac \pi 3 = \dfrac {\sqrt 3} 2$
{{begin-eqn}} {{eqn | l = \sin 60 \degrees | r = \map \cos {90 \degrees - 60 \degrees} | c = [[Cosine of Complement equals Sine]] }} {{eqn | r = \cos 30 \degrees | c = }} {{eqn | r = \dfrac {\sqrt 3} 2 | c = [[Cosine of 30 Degrees|Cosine of $30 \degrees$]] }} {{end-eqn}} {{qed}}
Sine of 60 Degrees
https://proofwiki.org/wiki/Sine_of_60_Degrees
https://proofwiki.org/wiki/Sine_of_60_Degrees
[ "Sine Function" ]
[]
[ "Cosine of Complement equals Sine", "Cosine of 30 Degrees" ]
proofwiki-7910
Sine of 75 Degrees
:$\sin 75 \degrees = \sin \dfrac {5 \pi} {12} = \dfrac {\sqrt 6 + \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \sin 75 \degrees | r = \map \sin {60 \degrees + 15 \degrees} | c = }} {{eqn | r = \sin 60 \degrees \cos 15 \degrees + \cos 60 \degrees \sin 15 \degrees | c = Sine of Sum }} {{eqn | r = \paren {\frac {\sqrt 3} 2} \paren {\frac {\sqrt 6 + \sqrt 2} 4} + \paren {\frac 1 2} \pare...
:$\sin 75 \degrees = \sin \dfrac {5 \pi} {12} = \dfrac {\sqrt 6 + \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \sin 75 \degrees | r = \map \sin {60 \degrees + 15 \degrees} | c = }} {{eqn | r = \sin 60 \degrees \cos 15 \degrees + \cos 60 \degrees \sin 15 \degrees | c = [[Sine of Sum]] }} {{eqn | r = \paren {\frac {\sqrt 3} 2} \paren {\frac {\sqrt 6 + \sqrt 2} 4} + \paren {\frac 1 2} \...
Sine of 75 Degrees/Proof 1
https://proofwiki.org/wiki/Sine_of_75_Degrees
https://proofwiki.org/wiki/Sine_of_75_Degrees/Proof_1
[ "Sine Function", "Sine of 75 Degrees" ]
[]
[ "Sine of Sum", "Sine of 60 Degrees", "Cosine of 15 Degrees", "Cosine of 60 Degrees", "Sine of 15 Degrees" ]
proofwiki-7911
Sine of 75 Degrees
:$\sin 75 \degrees = \sin \dfrac {5 \pi} {12} = \dfrac {\sqrt 6 + \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \sin 75 \degrees | r = \map \cos {90 \degrees - 75 \degrees} | c = Cosine of Complement equals Sine }} {{eqn | r = \cos 15^\circ | c = }} {{eqn | r = \frac {\sqrt 6 + \sqrt 2} 4 | c = Cosine of $15 \degrees$ }} {{end-eqn}} {{qed}}
:$\sin 75 \degrees = \sin \dfrac {5 \pi} {12} = \dfrac {\sqrt 6 + \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \sin 75 \degrees | r = \map \cos {90 \degrees - 75 \degrees} | c = [[Cosine of Complement equals Sine]] }} {{eqn | r = \cos 15^\circ | c = }} {{eqn | r = \frac {\sqrt 6 + \sqrt 2} 4 | c = [[Cosine of 15 Degrees|Cosine of $15 \degrees$]] }} {{end-eqn}} {{qed}}
Sine of 75 Degrees/Proof 2
https://proofwiki.org/wiki/Sine_of_75_Degrees
https://proofwiki.org/wiki/Sine_of_75_Degrees/Proof_2
[ "Sine Function", "Sine of 75 Degrees" ]
[]
[ "Cosine of Complement equals Sine", "Cosine of 15 Degrees" ]
proofwiki-7912
Sine of Right Angle
:$\sin 90 \degrees = \sin \dfrac \pi 2 = 1$
A direct implementation of Sine of Half-Integer Multiple of Pi: :$\forall n \in \Z: \map \sin {n + \dfrac 1 2} \pi = \paren {-1}^n$ In this case, $n = 0$ and so: :$\sin \dfrac 1 2 \pi = \paren {-1}^0 = 1$ {{qed}}
:$\sin 90 \degrees = \sin \dfrac \pi 2 = 1$
A direct implementation of [[Sine of Half-Integer Multiple of Pi]]: :$\forall n \in \Z: \map \sin {n + \dfrac 1 2} \pi = \paren {-1}^n$ In this case, $n = 0$ and so: :$\sin \dfrac 1 2 \pi = \paren {-1}^0 = 1$ {{qed}}
Sine of Right Angle
https://proofwiki.org/wiki/Sine_of_Right_Angle
https://proofwiki.org/wiki/Sine_of_Right_Angle
[ "Sine Function" ]
[]
[ "Sine of Half-Integer Multiple of Pi" ]
proofwiki-7913
Sine of Angle plus Right Angle
: $\sin \paren {x + \dfrac \pi 2} = \cos x$
{{begin-eqn}} {{eqn | l = \sin \paren {x + \frac \pi 2} | r = \sin x \cos \frac \pi 2 + \cos x \sin \frac \pi 2 | c = Sine of Sum }} {{eqn | r = \sin x \cdot 0 + \cos x \cdot 1 | c = Cosine of Right Angle and Sine of Right Angle }} {{eqn | r = \cos x | c = }} {{end-eqn}} {{qed}}
: $\sin \paren {x + \dfrac \pi 2} = \cos x$
{{begin-eqn}} {{eqn | l = \sin \paren {x + \frac \pi 2} | r = \sin x \cos \frac \pi 2 + \cos x \sin \frac \pi 2 | c = [[Sine of Sum]] }} {{eqn | r = \sin x \cdot 0 + \cos x \cdot 1 | c = [[Cosine of Right Angle]] and [[Sine of Right Angle]] }} {{eqn | r = \cos x | c = }} {{end-eqn}} {{qed}}
Sine of Angle plus Right Angle
https://proofwiki.org/wiki/Sine_of_Angle_plus_Right_Angle
https://proofwiki.org/wiki/Sine_of_Angle_plus_Right_Angle
[ "Sine Function", "Reduction Formulae (Trigonometry)" ]
[]
[ "Sine of Sum", "Cosine of Right Angle", "Sine of Right Angle" ]
proofwiki-7914
Sine of 105 Degrees
:$\sin 105^\circ = \sin \dfrac {7 \pi} {12} = \dfrac {\sqrt 6 + \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \sin 105^\circ | r = \sin \left({90^\circ + 15^\circ}\right) | c = }} {{eqn | r = \cos 15^\circ | c = Sine of Angle plus Right Angle }} {{eqn | r = \frac {\sqrt 6 + \sqrt 2} 4 | c = Cosine of 15 Degrees }} {{end-eqn}} {{qed}}
:$\sin 105^\circ = \sin \dfrac {7 \pi} {12} = \dfrac {\sqrt 6 + \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \sin 105^\circ | r = \sin \left({90^\circ + 15^\circ}\right) | c = }} {{eqn | r = \cos 15^\circ | c = [[Sine of Angle plus Right Angle]] }} {{eqn | r = \frac {\sqrt 6 + \sqrt 2} 4 | c = [[Cosine of 15 Degrees]] }} {{end-eqn}} {{qed}}
Sine of 105 Degrees
https://proofwiki.org/wiki/Sine_of_105_Degrees
https://proofwiki.org/wiki/Sine_of_105_Degrees
[ "Sine Function" ]
[]
[ "Sine of Angle plus Right Angle", "Cosine of 15 Degrees" ]
proofwiki-7915
Sine of 120 Degrees
:$\sin 120 \degrees = \sin \dfrac {2 \pi} 3 = \dfrac {\sqrt 3} 2$
{{begin-eqn}} {{eqn | l = \sin 120 \degrees | r = \map \sin {90 \degrees + 30 \degrees} | c = }} {{eqn | r = \cos 30 \degrees | c = Sine of Angle plus Right Angle }} {{eqn | r = \frac {\sqrt 3} 2 | c = Cosine of $30 \degrees$ }} {{end-eqn}} {{qed}}
:$\sin 120 \degrees = \sin \dfrac {2 \pi} 3 = \dfrac {\sqrt 3} 2$
{{begin-eqn}} {{eqn | l = \sin 120 \degrees | r = \map \sin {90 \degrees + 30 \degrees} | c = }} {{eqn | r = \cos 30 \degrees | c = [[Sine of Angle plus Right Angle]] }} {{eqn | r = \frac {\sqrt 3} 2 | c = [[Cosine of 30 Degrees|Cosine of $30 \degrees$]] }} {{end-eqn}} {{qed}}
Sine of 120 Degrees
https://proofwiki.org/wiki/Sine_of_120_Degrees
https://proofwiki.org/wiki/Sine_of_120_Degrees
[ "Sine Function" ]
[]
[ "Sine of Angle plus Right Angle", "Cosine of 30 Degrees" ]
proofwiki-7916
Sine of 135 Degrees
:$\sin 135 \degrees = \sin \dfrac {3 \pi} 4 = \dfrac {\sqrt 2} 2$
{{begin-eqn}} {{eqn | l = \sin 135 \degrees | r = \map \sin {90 \degrees + 45 \degrees} | c = }} {{eqn | r = \cos 45 \degrees | c = Sine of Angle plus Right Angle }} {{eqn | r = \frac {\sqrt 2} 2 | c = Cosine of $45 \degrees$ }} {{end-eqn}} {{qed}}
:$\sin 135 \degrees = \sin \dfrac {3 \pi} 4 = \dfrac {\sqrt 2} 2$
{{begin-eqn}} {{eqn | l = \sin 135 \degrees | r = \map \sin {90 \degrees + 45 \degrees} | c = }} {{eqn | r = \cos 45 \degrees | c = [[Sine of Angle plus Right Angle]] }} {{eqn | r = \frac {\sqrt 2} 2 | c = [[Cosine of 45 Degrees|Cosine of $45 \degrees$]] }} {{end-eqn}} {{qed}}
Sine of 135 Degrees
https://proofwiki.org/wiki/Sine_of_135_Degrees
https://proofwiki.org/wiki/Sine_of_135_Degrees
[ "Sine Function" ]
[]
[ "Sine of Angle plus Right Angle", "Cosine of 45 Degrees" ]
proofwiki-7917
Sine of 150 Degrees
:$\sin 150 \degrees = \sin \dfrac {5 \pi} 6 = \dfrac 1 2$
{{begin-eqn}} {{eqn | l = \sin 150 \degrees | r = \map \sin {90 \degrees + 60 \degrees} | c = }} {{eqn | r = \cos 60 \degrees | c = Sine of Angle plus Right Angle }} {{eqn | r = \frac 1 2 | c = Cosine of $60 \degrees$ }} {{end-eqn}} {{qed}}
:$\sin 150 \degrees = \sin \dfrac {5 \pi} 6 = \dfrac 1 2$
{{begin-eqn}} {{eqn | l = \sin 150 \degrees | r = \map \sin {90 \degrees + 60 \degrees} | c = }} {{eqn | r = \cos 60 \degrees | c = [[Sine of Angle plus Right Angle]] }} {{eqn | r = \frac 1 2 | c = [[Cosine of 60 Degrees|Cosine of $60 \degrees$]] }} {{end-eqn}} {{qed}}
Sine of 150 Degrees
https://proofwiki.org/wiki/Sine_of_150_Degrees
https://proofwiki.org/wiki/Sine_of_150_Degrees
[ "Sine Function" ]
[]
[ "Sine of Angle plus Right Angle", "Cosine of 60 Degrees" ]
proofwiki-7918
Sine of 165 Degrees
:$\sin 165 \degrees = \sin \dfrac {11 \pi} {12} = \dfrac {\sqrt 6 - \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \sin 165 \degrees | r = \map \sin {90 \degrees + 75 \degrees} | c = }} {{eqn | r = \cos 75 \degrees | c = Sine of Angle plus Right Angle }} {{eqn | r = \frac {\sqrt 6 - \sqrt 2} 4 | c = Cosine of $75 \degrees$ }} {{end-eqn}} {{qed}}
:$\sin 165 \degrees = \sin \dfrac {11 \pi} {12} = \dfrac {\sqrt 6 - \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \sin 165 \degrees | r = \map \sin {90 \degrees + 75 \degrees} | c = }} {{eqn | r = \cos 75 \degrees | c = [[Sine of Angle plus Right Angle]] }} {{eqn | r = \frac {\sqrt 6 - \sqrt 2} 4 | c = [[Cosine of 75 Degrees|Cosine of $75 \degrees$]] }} {{end-eqn}} {{qed}}
Sine of 165 Degrees
https://proofwiki.org/wiki/Sine_of_165_Degrees
https://proofwiki.org/wiki/Sine_of_165_Degrees
[ "Sine Function" ]
[]
[ "Sine of Angle plus Right Angle", "Cosine of 75 Degrees" ]
proofwiki-7919
Sine of Straight Angle
:$\sin 180 \degrees = \sin \pi = 0$
A direct implementation of Sine of Multiple of Pi: :$\forall n \in \Z: \sin n \pi = 0$ In this case, $n = 1$ and so: :$\sin \pi = 0$ {{qed}}
:$\sin 180 \degrees = \sin \pi = 0$
A direct implementation of [[Sine of Multiple of Pi]]: :$\forall n \in \Z: \sin n \pi = 0$ In this case, $n = 1$ and so: :$\sin \pi = 0$ {{qed}}
Sine of Straight Angle
https://proofwiki.org/wiki/Sine_of_Straight_Angle
https://proofwiki.org/wiki/Sine_of_Straight_Angle
[ "Sine Function" ]
[]
[ "Sine of Integer Multiple of Pi" ]
proofwiki-7920
Sine of Supplementary Angle
:$\map \sin {\pi - \theta} = \sin \theta$ where $\sin$ denotes sine. That is, the sine of an angle equals its supplement.
{{begin-eqn}} {{eqn | l = \map \sin {\pi - \theta} | r = \sin \pi \cos \theta - \cos \pi \sin \theta | c = Sine of Difference }} {{eqn | r = 0 \times \cos \theta - \paren {-1} \times \sin \theta | c = Sine of Straight Angle and Cosine of Straight Angle }} {{eqn | r = \sin \theta }} {{end-eqn}} {{qed}}
:$\map \sin {\pi - \theta} = \sin \theta$ where $\sin$ denotes [[Definition:Sine|sine]]. That is, the [[Definition:Sine|sine]] of an [[Definition:Angle|angle]] equals its [[Definition:Supplement of Angle|supplement]].
{{begin-eqn}} {{eqn | l = \map \sin {\pi - \theta} | r = \sin \pi \cos \theta - \cos \pi \sin \theta | c = [[Sine of Difference]] }} {{eqn | r = 0 \times \cos \theta - \paren {-1} \times \sin \theta | c = [[Sine of Straight Angle]] and [[Cosine of Straight Angle]] }} {{eqn | r = \sin \theta }} {{end-e...
Sine of Supplementary Angle
https://proofwiki.org/wiki/Sine_of_Supplementary_Angle
https://proofwiki.org/wiki/Sine_of_Supplementary_Angle
[ "Sine Function", "Supplementary Angles" ]
[ "Definition:Sine", "Definition:Sine", "Definition:Angle", "Definition:Supplementary Angles" ]
[ "Sine of Difference", "Sine of Straight Angle", "Cosine of Straight Angle" ]
proofwiki-7921
Cosine of Supplementary Angle
:$\map \cos {\pi - \theta} = -\cos \theta$ where $\cos$ denotes cosine. That is, the cosine of an angle is the negative of its supplement.
{{begin-eqn}} {{eqn | l = \map \cos {\pi - \theta} | r = \cos \pi \cos \theta + \sin \pi \sin \theta | c = Cosine of Difference }} {{eqn | r = \paren {-1} \times \cos \theta + 0 \times \sin \theta | c = Cosine of Straight Angle and Sine of Straight Angle }} {{eqn | r = -\cos \theta }} {{end-eqn}} {{qe...
:$\map \cos {\pi - \theta} = -\cos \theta$ where $\cos$ denotes [[Definition:Cosine|cosine]]. That is, the [[Definition:Cosine|cosine]] of an [[Definition:Angle|angle]] is the negative of its [[Definition:Supplement of Angle|supplement]].
{{begin-eqn}} {{eqn | l = \map \cos {\pi - \theta} | r = \cos \pi \cos \theta + \sin \pi \sin \theta | c = [[Cosine of Difference]] }} {{eqn | r = \paren {-1} \times \cos \theta + 0 \times \sin \theta | c = [[Cosine of Straight Angle]] and [[Sine of Straight Angle]] }} {{eqn | r = -\cos \theta }} {{en...
Cosine of Supplementary Angle
https://proofwiki.org/wiki/Cosine_of_Supplementary_Angle
https://proofwiki.org/wiki/Cosine_of_Supplementary_Angle
[ "Cosine of Supplementary Angle", "Cosine Function", "Supplementary Angles" ]
[ "Definition:Cosine", "Definition:Cosine", "Definition:Angle", "Definition:Supplementary Angles" ]
[ "Cosine of Difference", "Cosine of Straight Angle", "Sine of Straight Angle" ]
proofwiki-7922
Sine of Conjugate Angle
:$\map \sin {2 \pi - \theta} = -\sin \theta$ where $\sin$ denotes sine. That is, the sine of an angle is the negative of its conjugate.
{{begin-eqn}} {{eqn | l = \map \sin {2 \pi - \theta} | r = \map \sin {2 \pi} \cos \theta - \map \cos {2 \pi} \sin \theta | c = Sine of Difference }} {{eqn | r = 0 \times \cos \theta - 1 \times \sin \theta | c = Sine of Full Angle and Cosine of Full Angle }} {{eqn | r = -\sin \theta }} {{end-eqn}} {{qe...
:$\map \sin {2 \pi - \theta} = -\sin \theta$ where $\sin$ denotes [[Definition:Sine|sine]]. That is, the [[Definition:Sine|sine]] of an [[Definition:Angle|angle]] is the negative of its [[Definition:Conjugate Angle|conjugate]].
{{begin-eqn}} {{eqn | l = \map \sin {2 \pi - \theta} | r = \map \sin {2 \pi} \cos \theta - \map \cos {2 \pi} \sin \theta | c = [[Sine of Difference]] }} {{eqn | r = 0 \times \cos \theta - 1 \times \sin \theta | c = [[Sine of Full Angle]] and [[Cosine of Full Angle]] }} {{eqn | r = -\sin \theta }} {{en...
Sine of Conjugate Angle
https://proofwiki.org/wiki/Sine_of_Conjugate_Angle
https://proofwiki.org/wiki/Sine_of_Conjugate_Angle
[ "Sine Function", "Conjugate Angles" ]
[ "Definition:Sine", "Definition:Sine", "Definition:Angle", "Definition:Conjugate Angles" ]
[ "Sine of Difference", "Sine of Full Angle", "Cosine of Full Angle" ]
proofwiki-7923
Cosine of Conjugate Angle
:$\map \cos {2 \pi - \theta} = \cos \theta$ where $\cos$ denotes cosine. That is, the cosine of an angle equals its conjugate.
{{begin-eqn}} {{eqn | l = \map \cos {2 \pi - \theta} | r = \map \cos {2 \pi} \cos \theta + \map \sin {2 \pi} \sin \theta | c = Cosine of Difference }} {{eqn | r = 1 \times \cos \theta + 0 \times \sin \theta | c = Cosine of Full Angle and Sine of Full Angle }} {{eqn | r = \cos \theta }} {{end-eqn}} {{q...
:$\map \cos {2 \pi - \theta} = \cos \theta$ where $\cos$ denotes [[Definition:Cosine|cosine]]. That is, the [[Definition:Cosine|cosine]] of an [[Definition:Angle|angle]] equals its [[Definition:Conjugate Angle|conjugate]].
{{begin-eqn}} {{eqn | l = \map \cos {2 \pi - \theta} | r = \map \cos {2 \pi} \cos \theta + \map \sin {2 \pi} \sin \theta | c = [[Cosine of Difference]] }} {{eqn | r = 1 \times \cos \theta + 0 \times \sin \theta | c = [[Cosine of Full Angle]] and [[Sine of Full Angle]] }} {{eqn | r = \cos \theta }} {{e...
Cosine of Conjugate Angle
https://proofwiki.org/wiki/Cosine_of_Conjugate_Angle
https://proofwiki.org/wiki/Cosine_of_Conjugate_Angle
[ "Cosine Function", "Conjugate Angles" ]
[ "Definition:Cosine", "Definition:Cosine", "Definition:Angle", "Definition:Conjugate Angles" ]
[ "Cosine of Difference", "Cosine of Full Angle", "Sine of Full Angle" ]
proofwiki-7924
Sine of 195 Degrees
:$\sin 195 \degrees = \sin \dfrac {13 \pi} {12} = -\dfrac {\sqrt 6 - \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \sin 195 \degrees | r = \map \sin {360 \degrees - 165 \degrees} | c = }} {{eqn | r = -\sin 165 \degrees | c = Sine of Conjugate Angle }} {{eqn | r = -\frac {\sqrt 6 - \sqrt 2} 4 | c = Sine of $165 \degrees$ }} {{end-eqn}} {{qed}}
:$\sin 195 \degrees = \sin \dfrac {13 \pi} {12} = -\dfrac {\sqrt 6 - \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \sin 195 \degrees | r = \map \sin {360 \degrees - 165 \degrees} | c = }} {{eqn | r = -\sin 165 \degrees | c = [[Sine of Conjugate Angle]] }} {{eqn | r = -\frac {\sqrt 6 - \sqrt 2} 4 | c = [[Sine of 165 Degrees|Sine of $165 \degrees$]] }} {{end-eqn}} {{qed}}
Sine of 195 Degrees
https://proofwiki.org/wiki/Sine_of_195_Degrees
https://proofwiki.org/wiki/Sine_of_195_Degrees
[ "Sine Function" ]
[]
[ "Sine of Conjugate Angle", "Sine of 165 Degrees" ]
proofwiki-7925
Sine of 210 Degrees
:$\sin 210 \degrees = \sin \dfrac {7 \pi} 6 = -\dfrac 1 2$
{{begin-eqn}} {{eqn | l = \sin 210 \degrees | r = \map \sin {360 \degrees - 150 \degrees} | c = }} {{eqn | r = -\sin 150 \degrees | c = Sine of Conjugate Angle }} {{eqn | r = -\frac 1 2 | c = Sine of $150 \degrees$ }} {{end-eqn}} {{qed}}
:$\sin 210 \degrees = \sin \dfrac {7 \pi} 6 = -\dfrac 1 2$
{{begin-eqn}} {{eqn | l = \sin 210 \degrees | r = \map \sin {360 \degrees - 150 \degrees} | c = }} {{eqn | r = -\sin 150 \degrees | c = [[Sine of Conjugate Angle]] }} {{eqn | r = -\frac 1 2 | c = [[Sine of 150 Degrees|Sine of $150 \degrees$]] }} {{end-eqn}} {{qed}}
Sine of 210 Degrees
https://proofwiki.org/wiki/Sine_of_210_Degrees
https://proofwiki.org/wiki/Sine_of_210_Degrees
[ "Sine Function" ]
[]
[ "Sine of Conjugate Angle", "Sine of 150 Degrees" ]
proofwiki-7926
Sine of 225 Degrees
:$\sin 225 \degrees = \sin \dfrac {5 \pi} 4 = -\dfrac {\sqrt 2} 2$
{{begin-eqn}} {{eqn | l = \sin 225 \degrees | r = \map \sin {360 \degrees - 135 \degrees} | c = }} {{eqn | r = -\sin 135 \degrees | c = Sine of Conjugate Angle }} {{eqn | r = -\frac {\sqrt 2} 2 | c = Sine of $135 \degrees$ }} {{end-eqn}} {{qed}}
:$\sin 225 \degrees = \sin \dfrac {5 \pi} 4 = -\dfrac {\sqrt 2} 2$
{{begin-eqn}} {{eqn | l = \sin 225 \degrees | r = \map \sin {360 \degrees - 135 \degrees} | c = }} {{eqn | r = -\sin 135 \degrees | c = [[Sine of Conjugate Angle]] }} {{eqn | r = -\frac {\sqrt 2} 2 | c = [[Sine of 135 Degrees|Sine of $135 \degrees$]] }} {{end-eqn}} {{qed}}
Sine of 225 Degrees
https://proofwiki.org/wiki/Sine_of_225_Degrees
https://proofwiki.org/wiki/Sine_of_225_Degrees
[ "Sine Function" ]
[]
[ "Sine of Conjugate Angle", "Sine of 135 Degrees" ]
proofwiki-7927
Sine of 240 Degrees
:$\sin 240 \degrees = \sin \dfrac {4 \pi} 3 = -\dfrac {\sqrt 3} 2$
{{begin-eqn}} {{eqn | l = \sin 240 \degrees | r = \map \sin {360 \degrees - 120 \degrees} | c = }} {{eqn | r = -\sin 120 \degrees | c = Sine of Conjugate Angle }} {{eqn | r = -\frac {\sqrt 3} 2 | c = Sine of $120 \degrees$ }} {{end-eqn}} {{qed}}
:$\sin 240 \degrees = \sin \dfrac {4 \pi} 3 = -\dfrac {\sqrt 3} 2$
{{begin-eqn}} {{eqn | l = \sin 240 \degrees | r = \map \sin {360 \degrees - 120 \degrees} | c = }} {{eqn | r = -\sin 120 \degrees | c = [[Sine of Conjugate Angle]] }} {{eqn | r = -\frac {\sqrt 3} 2 | c = [[Sine of 120 Degrees|Sine of $120 \degrees$]] }} {{end-eqn}} {{qed}}
Sine of 240 Degrees/Proof 1
https://proofwiki.org/wiki/Sine_of_240_Degrees
https://proofwiki.org/wiki/Sine_of_240_Degrees/Proof_1
[ "Sine of 240 Degrees", "Sine Function" ]
[]
[ "Sine of Conjugate Angle", "Sine of 120 Degrees" ]
proofwiki-7928
Sine of 240 Degrees
:$\sin 240 \degrees = \sin \dfrac {4 \pi} 3 = -\dfrac {\sqrt 3} 2$
When $240 \degrees$ is embedded in a Cartesian plane, it makes an angle of $60 \degrees$ with the $x$-axis. $240 \degrees$ can be found in the third quadrant. Hence by definition of sine function in the third quadrant, $\sin 240 \degrees$ is negative. Thus: :$\sin 240 \degrees = -\sin 60 \degrees = -\dfrac {\sqrt 3} 2$...
:$\sin 240 \degrees = \sin \dfrac {4 \pi} 3 = -\dfrac {\sqrt 3} 2$
When $240 \degrees$ is embedded in a [[Definition:Cartesian Plane|Cartesian plane]], it makes an [[Definition:Angle|angle]] of $60 \degrees$ with the [[Definition:X-Axis|$x$-axis]]. $240 \degrees$ can be found in the [[Definition:Third Quadrant|third quadrant]]. Hence by definition of [[Definition:Sine/Definition fro...
Sine of 240 Degrees/Proof 2
https://proofwiki.org/wiki/Sine_of_240_Degrees
https://proofwiki.org/wiki/Sine_of_240_Degrees/Proof_2
[ "Sine of 240 Degrees", "Sine Function" ]
[]
[ "Definition:Cartesian Plane", "Definition:Angle", "Definition:Axis/X-Axis", "Definition:Cartesian Plane/Quadrants/Third", "Definition:Sine/Definition from Circle/Third Quadrant", "Definition:Negative Real Function" ]
proofwiki-7929
Sine of 255 Degrees
:$\sin 255^\circ = \sin \dfrac {17 \pi} {12} = - \dfrac {\sqrt 6 + \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \sin 255^\circ | r = \sin \left({360^\circ - 105^\circ}\right) | c = }} {{eqn | r = - \sin 105^\circ | c = Sine of Conjugate Angle }} {{eqn | r = - \frac {\sqrt 6 + \sqrt 2} 4 | c = Sine of 105 Degrees }} {{end-eqn}} {{qed}}
:$\sin 255^\circ = \sin \dfrac {17 \pi} {12} = - \dfrac {\sqrt 6 + \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \sin 255^\circ | r = \sin \left({360^\circ - 105^\circ}\right) | c = }} {{eqn | r = - \sin 105^\circ | c = [[Sine of Conjugate Angle]] }} {{eqn | r = - \frac {\sqrt 6 + \sqrt 2} 4 | c = [[Sine of 105 Degrees]] }} {{end-eqn}} {{qed}}
Sine of 255 Degrees
https://proofwiki.org/wiki/Sine_of_255_Degrees
https://proofwiki.org/wiki/Sine_of_255_Degrees
[ "Sine Function" ]
[]
[ "Sine of Conjugate Angle", "Sine of 105 Degrees" ]
proofwiki-7930
Sine of Three Right Angles
:$\sin 270 \degrees = \sin \dfrac {3 \pi} 2 = -1$
{{begin-eqn}} {{eqn | l = \sin 270 \degrees | r = \map \sin {360 \degrees - 90 \degrees} | c = }} {{eqn | r = -\sin 90 \degrees | c = Sine of Conjugate Angle }} {{eqn | r = -1 | c = Sine of Right Angle }} {{end-eqn}} {{qed}}
:$\sin 270 \degrees = \sin \dfrac {3 \pi} 2 = -1$
{{begin-eqn}} {{eqn | l = \sin 270 \degrees | r = \map \sin {360 \degrees - 90 \degrees} | c = }} {{eqn | r = -\sin 90 \degrees | c = [[Sine of Conjugate Angle]] }} {{eqn | r = -1 | c = [[Sine of Right Angle]] }} {{end-eqn}} {{qed}}
Sine of Three Right Angles
https://proofwiki.org/wiki/Sine_of_Three_Right_Angles
https://proofwiki.org/wiki/Sine_of_Three_Right_Angles
[ "Sine Function" ]
[]
[ "Sine of Conjugate Angle", "Sine of Right Angle" ]
proofwiki-7931
Sine of 285 Degrees
:$\sin 285^\circ = \sin \dfrac {19 \pi} {12} = - \dfrac {\sqrt 6 + \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \sin 285^\circ | r = \sin \left({360^\circ - 75^\circ}\right) | c = }} {{eqn | r = - \sin 75^\circ | c = Sine of Conjugate Angle }} {{eqn | r = - \dfrac {\sqrt 6 + \sqrt 2} 4 | c = Sine of $75^\circ$ }} {{end-eqn}} {{qed}}
:$\sin 285^\circ = \sin \dfrac {19 \pi} {12} = - \dfrac {\sqrt 6 + \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \sin 285^\circ | r = \sin \left({360^\circ - 75^\circ}\right) | c = }} {{eqn | r = - \sin 75^\circ | c = [[Sine of Conjugate Angle]] }} {{eqn | r = - \dfrac {\sqrt 6 + \sqrt 2} 4 | c = [[Sine of 75 Degrees|Sine of $75^\circ$]] }} {{end-eqn}} {{qed}}
Sine of 285 Degrees
https://proofwiki.org/wiki/Sine_of_285_Degrees
https://proofwiki.org/wiki/Sine_of_285_Degrees
[ "Sine Function" ]
[]
[ "Sine of Conjugate Angle", "Sine of 75 Degrees" ]
proofwiki-7932
Sine of 300 Degrees
:$\sin 300 \degrees = \sin \dfrac {5 \pi} 3 = -\dfrac {\sqrt 3} 2$
{{begin-eqn}} {{eqn | l = \sin 300 \degrees | r = \map \sin {360 \degrees - 60 \degrees} | c = }} {{eqn | r = -\sin 60 \degrees | c = Sine of Conjugate Angle }} {{eqn | r = -\dfrac {\sqrt 3} 2 | c = Sine of $60 \degrees$ }} {{end-eqn}} {{qed}}
:$\sin 300 \degrees = \sin \dfrac {5 \pi} 3 = -\dfrac {\sqrt 3} 2$
{{begin-eqn}} {{eqn | l = \sin 300 \degrees | r = \map \sin {360 \degrees - 60 \degrees} | c = }} {{eqn | r = -\sin 60 \degrees | c = [[Sine of Conjugate Angle]] }} {{eqn | r = -\dfrac {\sqrt 3} 2 | c = [[Sine of 60 Degrees|Sine of $60 \degrees$]] }} {{end-eqn}} {{qed}}
Sine of 300 Degrees
https://proofwiki.org/wiki/Sine_of_300_Degrees
https://proofwiki.org/wiki/Sine_of_300_Degrees
[ "Sine Function" ]
[]
[ "Sine of Conjugate Angle", "Sine of 60 Degrees" ]
proofwiki-7933
Sine of 315 Degrees
:$\sin 315 \degrees = \sin \dfrac {7 \pi} 4 = -\dfrac {\sqrt 2} 2$
{{begin-eqn}} {{eqn | l = \sin 315 \degrees | r = \map \sin {360 \degrees - 45 \degrees} | c = }} {{eqn | r = -\sin 45 \degrees | c = Sine of Conjugate Angle }} {{eqn | r = -\dfrac {\sqrt 2} 2 | c = Sine of $45 \degrees$ }} {{end-eqn}} {{qed}}
:$\sin 315 \degrees = \sin \dfrac {7 \pi} 4 = -\dfrac {\sqrt 2} 2$
{{begin-eqn}} {{eqn | l = \sin 315 \degrees | r = \map \sin {360 \degrees - 45 \degrees} | c = }} {{eqn | r = -\sin 45 \degrees | c = [[Sine of Conjugate Angle]] }} {{eqn | r = -\dfrac {\sqrt 2} 2 | c = [[Sine of 45 Degrees|Sine of $45 \degrees$]] }} {{end-eqn}} {{qed}}
Sine of 315 Degrees
https://proofwiki.org/wiki/Sine_of_315_Degrees
https://proofwiki.org/wiki/Sine_of_315_Degrees
[ "Sine Function" ]
[]
[ "Sine of Conjugate Angle", "Sine of 45 Degrees" ]
proofwiki-7934
Sine of 330 Degrees
:$\sin 330 \degrees = \sin \dfrac {11 \pi} 6 = -\dfrac 1 2$
{{begin-eqn}} {{eqn | l = \sin 330 \degrees | r = \map \sin {360 \degrees - 30 \degrees} | c = }} {{eqn | r = -\sin 30 \degrees | c = Sine of Conjugate Angle }} {{eqn | r = -\dfrac 1 2 | c = Sine of $30 \degrees$ }} {{end-eqn}} {{qed}}
:$\sin 330 \degrees = \sin \dfrac {11 \pi} 6 = -\dfrac 1 2$
{{begin-eqn}} {{eqn | l = \sin 330 \degrees | r = \map \sin {360 \degrees - 30 \degrees} | c = }} {{eqn | r = -\sin 30 \degrees | c = [[Sine of Conjugate Angle]] }} {{eqn | r = -\dfrac 1 2 | c = [[Sine of 30 Degrees|Sine of $30 \degrees$]] }} {{end-eqn}} {{qed}}
Sine of 330 Degrees
https://proofwiki.org/wiki/Sine_of_330_Degrees
https://proofwiki.org/wiki/Sine_of_330_Degrees
[ "Sine Function" ]
[]
[ "Sine of Conjugate Angle", "Sine of 30 Degrees" ]
proofwiki-7935
Sine of 345 Degrees
:$\sin 345 \degrees = \sin \dfrac {23 \pi} {12} = - \dfrac {\sqrt 6 - \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \sin 345 \degrees | r = \map \sin {360 \degrees - 15 \degrees} | c = }} {{eqn | r = -\sin 15 \degrees | c = Sine of Conjugate Angle }} {{eqn | r = -\dfrac {\sqrt 6 - \sqrt 2} 4 | c = {{sin|15}} }} {{end-eqn}} {{qed}}
:$\sin 345 \degrees = \sin \dfrac {23 \pi} {12} = - \dfrac {\sqrt 6 - \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \sin 345 \degrees | r = \map \sin {360 \degrees - 15 \degrees} | c = }} {{eqn | r = -\sin 15 \degrees | c = [[Sine of Conjugate Angle]] }} {{eqn | r = -\dfrac {\sqrt 6 - \sqrt 2} 4 | c = {{sin|15}} }} {{end-eqn}} {{qed}}
Sine of 345 Degrees
https://proofwiki.org/wiki/Sine_of_345_Degrees
https://proofwiki.org/wiki/Sine_of_345_Degrees
[ "Sine Function" ]
[]
[ "Sine of Conjugate Angle" ]
proofwiki-7936
Sine of Full Angle
:$\sin 360^\circ = \sin 2 \pi = 0$
A direct implementation of Sine of Multiple of Pi: :$\forall n \in \Z: \sin n \pi = 0$ In this case, $n = 2$ and so: :$\sin 2 \pi = 0$ {{qed}}
:$\sin 360^\circ = \sin 2 \pi = 0$
A direct implementation of [[Sine of Multiple of Pi]]: :$\forall n \in \Z: \sin n \pi = 0$ In this case, $n = 2$ and so: :$\sin 2 \pi = 0$ {{qed}}
Sine of Full Angle
https://proofwiki.org/wiki/Sine_of_Full_Angle
https://proofwiki.org/wiki/Sine_of_Full_Angle
[ "Sine Function" ]
[]
[ "Sine of Integer Multiple of Pi" ]
proofwiki-7937
Cosine of 15 Degrees
:$\cos 15 \degrees = \cos \dfrac \pi {12} = \dfrac {\sqrt 6 + \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \cos 15 \degrees | r = \cos \frac {30 \degrees} 2 | c = }} {{eqn | r = \sqrt {\frac {1 + \cos 30 \degrees} 2} | c = Half Angle Formula for Cosine: $\theta$ is in Quadrant I }} {{eqn | r = \sqrt {\frac {1 + \frac {\sqrt 3} 2} 2} | c = Cosine of $30 \degrees$ }} {{eqn | ...
:$\cos 15 \degrees = \cos \dfrac \pi {12} = \dfrac {\sqrt 6 + \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \cos 15 \degrees | r = \cos \frac {30 \degrees} 2 | c = }} {{eqn | r = \sqrt {\frac {1 + \cos 30 \degrees} 2} | c = [[Half Angle Formula for Cosine]]: $\theta$ is in [[Definition:Cosine/Definition from Circle/First Quadrant|Quadrant I]] }} {{eqn | r = \sqrt {\frac {1 + \frac...
Cosine of 15 Degrees/Proof 1
https://proofwiki.org/wiki/Cosine_of_15_Degrees
https://proofwiki.org/wiki/Cosine_of_15_Degrees/Proof_1
[ "Cosine Function", "Cosine of 15 Degrees" ]
[]
[ "Half Angle Formulas/Cosine", "Definition:Cosine/Definition from Circle/First Quadrant", "Cosine of 30 Degrees", "Definition:Cosine/Definition from Circle/First Quadrant" ]
proofwiki-7938
Cosine of 15 Degrees
:$\cos 15 \degrees = \cos \dfrac \pi {12} = \dfrac {\sqrt 6 + \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \cos 15 \degrees | r = \map \cos {45 \degrees - 30 \degrees} | c = }} {{eqn | r = \cos 45 \degrees \cos 30 \degrees + \sin 45 \degrees \sin 30 \degrees | c = Cosine of Difference }} {{eqn | r = \paren {\frac {\sqrt 2} 2} \paren {\frac {\sqrt 3} 2} + \paren {\frac {\sqrt 2} 2...
:$\cos 15 \degrees = \cos \dfrac \pi {12} = \dfrac {\sqrt 6 + \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \cos 15 \degrees | r = \map \cos {45 \degrees - 30 \degrees} | c = }} {{eqn | r = \cos 45 \degrees \cos 30 \degrees + \sin 45 \degrees \sin 30 \degrees | c = [[Cosine of Difference]] }} {{eqn | r = \paren {\frac {\sqrt 2} 2} \paren {\frac {\sqrt 3} 2} + \paren {\frac {\sqrt ...
Cosine of 15 Degrees/Proof 2
https://proofwiki.org/wiki/Cosine_of_15_Degrees
https://proofwiki.org/wiki/Cosine_of_15_Degrees/Proof_2
[ "Cosine Function", "Cosine of 15 Degrees" ]
[]
[ "Cosine of Difference", "Cosine of 45 Degrees", "Cosine of 30 Degrees", "Sine of 45 Degrees", "Sine of 30 Degrees" ]
proofwiki-7939
Cosine of 30 Degrees
:$\cos 30 \degrees = \cos \dfrac \pi 6 = \dfrac {\sqrt 3} 2$
{{begin-eqn}} {{eqn | l = \paren {\cos 30 \degrees}^2 | r = 1 - \paren {\sin 30 \degrees}^2 | c = Sum of Squares of Sine and Cosine }} {{eqn | r = 1 - \paren {\frac 1 2}^2 | c = {{sin|30}} }} {{eqn | r = \frac 3 4 | c = }} {{eqn | ll= \leadsto | l = \cos 30 \degrees | r = \sqrt {\fr...
:$\cos 30 \degrees = \cos \dfrac \pi 6 = \dfrac {\sqrt 3} 2$
{{begin-eqn}} {{eqn | l = \paren {\cos 30 \degrees}^2 | r = 1 - \paren {\sin 30 \degrees}^2 | c = [[Sum of Squares of Sine and Cosine]] }} {{eqn | r = 1 - \paren {\frac 1 2}^2 | c = {{sin|30}} }} {{eqn | r = \frac 3 4 | c = }} {{eqn | ll= \leadsto | l = \cos 30 \degrees | r = \sqrt ...
Cosine of 30 Degrees
https://proofwiki.org/wiki/Cosine_of_30_Degrees
https://proofwiki.org/wiki/Cosine_of_30_Degrees
[ "Cosine Function" ]
[]
[ "Sum of Squares of Sine and Cosine", "Definition:Positive/Real Number", "Definition:Cosine/Definition from Circle/First Quadrant" ]
proofwiki-7940
Cosine of 45 Degrees
:$\cos 45 \degrees = \cos \dfrac \pi 4 = \dfrac {\sqrt 2} 2$
{{begin-eqn}} {{eqn | l = \paren {\cos 45 \degrees}^2 | r = 1 - \paren {\sin 45 \degrees}^2 | c = Sum of Squares of Sine and Cosine }} {{eqn | r = 1 - \paren {\frac {\sqrt 2} 2}^2 | c = Sine of $45 \degrees$ }} {{eqn | r = \frac 1 2 | c = }} {{eqn | ll= \leadsto | l = \cos 45 \degrees ...
:$\cos 45 \degrees = \cos \dfrac \pi 4 = \dfrac {\sqrt 2} 2$
{{begin-eqn}} {{eqn | l = \paren {\cos 45 \degrees}^2 | r = 1 - \paren {\sin 45 \degrees}^2 | c = [[Sum of Squares of Sine and Cosine]] }} {{eqn | r = 1 - \paren {\frac {\sqrt 2} 2}^2 | c = [[Sine of 45 Degrees|Sine of $45 \degrees$]] }} {{eqn | r = \frac 1 2 | c = }} {{eqn | ll= \leadsto ...
Cosine of 45 Degrees
https://proofwiki.org/wiki/Cosine_of_45_Degrees
https://proofwiki.org/wiki/Cosine_of_45_Degrees
[ "Cosine of 45 Degrees", "Cosine Function" ]
[]
[ "Sum of Squares of Sine and Cosine", "Sine of 45 Degrees", "Definition:Positive/Real Number", "Definition:Cosine/Definition from Circle/First Quadrant" ]
proofwiki-7941
Cosine of 60 Degrees
:$\cos 60 \degrees = \cos \dfrac \pi 3 = \dfrac 1 2$
{{begin-eqn}} {{eqn | l = \cos 60 \degrees | r = \map \cos {90 \degrees - 30 \degrees} | c = }} {{eqn | r = \sin 30 \degrees | c = Cosine of Complement equals Sine }} {{eqn | r = \dfrac 1 2 | c = Sine of $30 \degrees$ }} {{end-eqn}} {{qed}}
:$\cos 60 \degrees = \cos \dfrac \pi 3 = \dfrac 1 2$
{{begin-eqn}} {{eqn | l = \cos 60 \degrees | r = \map \cos {90 \degrees - 30 \degrees} | c = }} {{eqn | r = \sin 30 \degrees | c = [[Cosine of Complement equals Sine]] }} {{eqn | r = \dfrac 1 2 | c = [[Sine of 30 Degrees|Sine of $30 \degrees$]] }} {{end-eqn}} {{qed}}
Cosine of 60 Degrees
https://proofwiki.org/wiki/Cosine_of_60_Degrees
https://proofwiki.org/wiki/Cosine_of_60_Degrees
[ "Cosine Function" ]
[]
[ "Cosine of Complement equals Sine", "Sine of 30 Degrees" ]
proofwiki-7942
Cosine of 75 Degrees
:$\cos 75^\circ = \cos \dfrac {5 \pi}{12} = \dfrac {\sqrt 6 - \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \cos 75^\circ | r = \cos \left({90^\circ - 15^\circ}\right) | c = }} {{eqn | r = \sin 15^\circ | c = Cosine of Complement equals Sine }} {{eqn | r = \dfrac {\sqrt 6 - \sqrt 2} 4 | c = Sine of $15^\circ$ }} {{end-eqn}} {{qed}}
:$\cos 75^\circ = \cos \dfrac {5 \pi}{12} = \dfrac {\sqrt 6 - \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \cos 75^\circ | r = \cos \left({90^\circ - 15^\circ}\right) | c = }} {{eqn | r = \sin 15^\circ | c = [[Cosine of Complement equals Sine]] }} {{eqn | r = \dfrac {\sqrt 6 - \sqrt 2} 4 | c = [[Sine of 15 Degrees|Sine of $15^\circ$]] }} {{end-eqn}} {{qed}}
Cosine of 75 Degrees
https://proofwiki.org/wiki/Cosine_of_75_Degrees
https://proofwiki.org/wiki/Cosine_of_75_Degrees
[ "Cosine Function" ]
[]
[ "Cosine of Complement equals Sine", "Sine of 15 Degrees" ]
proofwiki-7943
Cosine of Right Angle
:$\cos 90 \degrees = \cos \dfrac \pi 2 = 0$
A direct implementation of Cosine of Half-Integer Multiple of Pi: :$\forall n \in \Z: \map \cos {n + \dfrac 1 2} \pi = 0$ In this case, $n = 0$ and so: :$\cos \dfrac 1 2 \pi = 0$ {{qed}}
:$\cos 90 \degrees = \cos \dfrac \pi 2 = 0$
A direct implementation of [[Cosine of Half-Integer Multiple of Pi]]: :$\forall n \in \Z: \map \cos {n + \dfrac 1 2} \pi = 0$ In this case, $n = 0$ and so: :$\cos \dfrac 1 2 \pi = 0$ {{qed}}
Cosine of Right Angle
https://proofwiki.org/wiki/Cosine_of_Right_Angle
https://proofwiki.org/wiki/Cosine_of_Right_Angle
[ "Cosine Function" ]
[]
[ "Cosine of Half-Integer Multiple of Pi" ]
proofwiki-7944
Cosine of 105 Degrees
:$\cos 105 \degrees = \cos \dfrac {7 \pi} {12} = - \dfrac {\sqrt 6 - \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \cos 105 \degrees | r = \map \cos {90 \degrees + 15 \degrees} | c = }} {{eqn | r = -\sin 15 \degrees | c = Cosine of Angle plus Right Angle }} {{eqn | r = -\frac {\sqrt 6 - \sqrt 2} 4 | c = Sine of $15 \degrees$ }} {{end-eqn}} {{qed}}
:$\cos 105 \degrees = \cos \dfrac {7 \pi} {12} = - \dfrac {\sqrt 6 - \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \cos 105 \degrees | r = \map \cos {90 \degrees + 15 \degrees} | c = }} {{eqn | r = -\sin 15 \degrees | c = [[Cosine of Angle plus Right Angle]] }} {{eqn | r = -\frac {\sqrt 6 - \sqrt 2} 4 | c = [[Sine of 15 Degrees|Sine of $15 \degrees$]] }} {{end-eqn}} {{qed}}
Cosine of 105 Degrees
https://proofwiki.org/wiki/Cosine_of_105_Degrees
https://proofwiki.org/wiki/Cosine_of_105_Degrees
[ "Cosine Function" ]
[]
[ "Cosine of Angle plus Right Angle", "Sine of 15 Degrees" ]
proofwiki-7945
Cosine of Angle plus Right Angle
:$\map \cos {x + \dfrac \pi 2} = -\sin x$
{{begin-eqn}} {{eqn | l = \map \cos {x + \frac \pi 2} | r = \cos x \cos \frac \pi 2 - \sin x \sin \frac \pi 2 | c = Cosine of Sum }} {{eqn | r = \cos x \cdot 0 - \sin x \cdot 1 | c = Cosine of Right Angle and Sine of Right Angle }} {{eqn | r = -\sin x | c = }} {{end-eqn}} {{qed}}
:$\map \cos {x + \dfrac \pi 2} = -\sin x$
{{begin-eqn}} {{eqn | l = \map \cos {x + \frac \pi 2} | r = \cos x \cos \frac \pi 2 - \sin x \sin \frac \pi 2 | c = [[Cosine of Sum]] }} {{eqn | r = \cos x \cdot 0 - \sin x \cdot 1 | c = [[Cosine of Right Angle]] and [[Sine of Right Angle]] }} {{eqn | r = -\sin x | c = }} {{end-eqn}} {{qed}}
Cosine of Angle plus Right Angle
https://proofwiki.org/wiki/Cosine_of_Angle_plus_Right_Angle
https://proofwiki.org/wiki/Cosine_of_Angle_plus_Right_Angle
[ "Cosine Function", "Reduction Formulae (Trigonometry)" ]
[]
[ "Cosine of Sum", "Cosine of Right Angle", "Sine of Right Angle" ]
proofwiki-7946
Cosine of 120 Degrees
:$\cos 120 \degrees = \cos \dfrac {2 \pi} 3 = -\dfrac 1 2$
{{begin-eqn}} {{eqn | l = \cos 120 \degrees | r = \map \cos {90 \degrees + 30 \degrees} | c = }} {{eqn | r = -\sin 30 \degrees | c = Cosine of Angle plus Right Angle }} {{eqn | r = -\frac 1 2 | c = {{sin|30}} }} {{end-eqn}} {{qed}}
:$\cos 120 \degrees = \cos \dfrac {2 \pi} 3 = -\dfrac 1 2$
{{begin-eqn}} {{eqn | l = \cos 120 \degrees | r = \map \cos {90 \degrees + 30 \degrees} | c = }} {{eqn | r = -\sin 30 \degrees | c = [[Cosine of Angle plus Right Angle]] }} {{eqn | r = -\frac 1 2 | c = {{sin|30}} }} {{end-eqn}} {{qed}}
Cosine of 120 Degrees
https://proofwiki.org/wiki/Cosine_of_120_Degrees
https://proofwiki.org/wiki/Cosine_of_120_Degrees
[ "Cosine Function" ]
[]
[ "Cosine of Angle plus Right Angle" ]
proofwiki-7947
Cosine of 135 Degrees
:$\cos 135 \degrees = \cos \dfrac {3 \pi} 4 = -\dfrac {\sqrt 2} 2$
{{begin-eqn}} {{eqn | l = \cos 135 \degrees | r = \map \cos {90 \degrees + 45 \degrees} | c = }} {{eqn | r = -\sin 45 \degrees | c = Cosine of Angle plus Right Angle }} {{eqn | r = -\frac {\sqrt 2} 2 | c = Sine of $45 \degrees$ }} {{end-eqn}} {{qed}}
:$\cos 135 \degrees = \cos \dfrac {3 \pi} 4 = -\dfrac {\sqrt 2} 2$
{{begin-eqn}} {{eqn | l = \cos 135 \degrees | r = \map \cos {90 \degrees + 45 \degrees} | c = }} {{eqn | r = -\sin 45 \degrees | c = [[Cosine of Angle plus Right Angle]] }} {{eqn | r = -\frac {\sqrt 2} 2 | c = [[Sine of 45 Degrees|Sine of $45 \degrees$]] }} {{end-eqn}} {{qed}}
Cosine of 135 Degrees
https://proofwiki.org/wiki/Cosine_of_135_Degrees
https://proofwiki.org/wiki/Cosine_of_135_Degrees
[ "Cosine Function" ]
[]
[ "Cosine of Angle plus Right Angle", "Sine of 45 Degrees" ]
proofwiki-7948
Cosine of 150 Degrees
:$\cos 150 \degrees = \cos \dfrac {5 \pi} 6 = -\dfrac {\sqrt 3} 2$
{{begin-eqn}} {{eqn | l = \cos 150 \degrees | r = \map \cos {90 \degrees + 60 \degrees} | c = }} {{eqn | r = -\sin 60 \degrees | c = Cosine of Angle plus Right Angle }} {{eqn | r = -\frac {\sqrt 3} 2 | c = Sine of $60 \degrees$ }} {{end-eqn}} {{qed}}
:$\cos 150 \degrees = \cos \dfrac {5 \pi} 6 = -\dfrac {\sqrt 3} 2$
{{begin-eqn}} {{eqn | l = \cos 150 \degrees | r = \map \cos {90 \degrees + 60 \degrees} | c = }} {{eqn | r = -\sin 60 \degrees | c = [[Cosine of Angle plus Right Angle]] }} {{eqn | r = -\frac {\sqrt 3} 2 | c = [[Sine of 60 Degrees|Sine of $60 \degrees$]] }} {{end-eqn}} {{qed}}
Cosine of 150 Degrees
https://proofwiki.org/wiki/Cosine_of_150_Degrees
https://proofwiki.org/wiki/Cosine_of_150_Degrees
[ "Cosine Function" ]
[]
[ "Cosine of Angle plus Right Angle", "Sine of 60 Degrees" ]
proofwiki-7949
Cosine of 165 Degrees
:$\cos 165 \degrees = \cos \dfrac {11 \pi} {12} = - \dfrac {\sqrt 6 + \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \cos 165 \degrees | r = \map \cos {90 \degrees + 75 \degrees} | c = }} {{eqn | r = -\sin 75 \degrees | c = Cosine of Angle plus Right Angle }} {{eqn | r = -\dfrac {\sqrt 6 + \sqrt 2} 4 | c = Sine of $75 \degrees$ }} {{end-eqn}} {{qed}}
:$\cos 165 \degrees = \cos \dfrac {11 \pi} {12} = - \dfrac {\sqrt 6 + \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \cos 165 \degrees | r = \map \cos {90 \degrees + 75 \degrees} | c = }} {{eqn | r = -\sin 75 \degrees | c = [[Cosine of Angle plus Right Angle]] }} {{eqn | r = -\dfrac {\sqrt 6 + \sqrt 2} 4 | c = [[Sine of 75 Degrees|Sine of $75 \degrees$]] }} {{end-eqn}} {{qed}}
Cosine of 165 Degrees
https://proofwiki.org/wiki/Cosine_of_165_Degrees
https://proofwiki.org/wiki/Cosine_of_165_Degrees
[ "Cosine Function" ]
[]
[ "Cosine of Angle plus Right Angle", "Sine of 75 Degrees" ]
proofwiki-7950
Cosine of Straight Angle
:$\cos 180 \degrees = \cos \pi = -1$
A direct implementation of Cosine of Multiple of Pi: :$\forall n \in \Z: \cos n \pi = \paren {-1}^n$ In this case, $n = 1$ and so: :$\cos \pi = -1^1 = -1$ {{qed}}
:$\cos 180 \degrees = \cos \pi = -1$
A direct implementation of [[Cosine of Multiple of Pi]]: :$\forall n \in \Z: \cos n \pi = \paren {-1}^n$ In this case, $n = 1$ and so: :$\cos \pi = -1^1 = -1$ {{qed}}
Cosine of Straight Angle
https://proofwiki.org/wiki/Cosine_of_Straight_Angle
https://proofwiki.org/wiki/Cosine_of_Straight_Angle
[ "Cosine Function" ]
[]
[ "Cosine of Integer Multiple of Pi" ]
proofwiki-7951
Cosine of 195 Degrees
:$\cos 195 \degrees = \cos \dfrac {13 \pi} {12} = - \dfrac {\sqrt 6 + \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \cos 195 \degrees | r = \cos \paren {360 \degrees - 165 \degrees} | c = }} {{eqn | r = \cos 165 \degrees | c = Cosine of Conjugate Angle }} {{eqn | r = - \frac {\sqrt 6 + \sqrt 2} 4 | c = Cosine of $165 \degrees$ }} {{end-eqn}} {{qed}}
:$\cos 195 \degrees = \cos \dfrac {13 \pi} {12} = - \dfrac {\sqrt 6 + \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \cos 195 \degrees | r = \cos \paren {360 \degrees - 165 \degrees} | c = }} {{eqn | r = \cos 165 \degrees | c = [[Cosine of Conjugate Angle]] }} {{eqn | r = - \frac {\sqrt 6 + \sqrt 2} 4 | c = [[Cosine of 165 Degrees|Cosine of $165 \degrees$]] }} {{end-eqn}} {{qed}}
Cosine of 195 Degrees
https://proofwiki.org/wiki/Cosine_of_195_Degrees
https://proofwiki.org/wiki/Cosine_of_195_Degrees
[ "Cosine Function" ]
[]
[ "Cosine of Conjugate Angle", "Cosine of 165 Degrees" ]
proofwiki-7952
Cosine of 210 Degrees
:$\cos 210 \degrees = \cos \dfrac {7 \pi} 6 = -\dfrac {\sqrt 3} 2$
{{begin-eqn}} {{eqn | l = \cos 210 \degrees | r = \map \cos {360 \degrees - 150 \degrees} | c = }} {{eqn | r = \cos 150 \degrees | c = Cosine of Conjugate Angle }} {{eqn | r = -\frac {\sqrt 3} 2 | c = Cosine of $150 \degrees$ }} {{end-eqn}} {{qed}}
:$\cos 210 \degrees = \cos \dfrac {7 \pi} 6 = -\dfrac {\sqrt 3} 2$
{{begin-eqn}} {{eqn | l = \cos 210 \degrees | r = \map \cos {360 \degrees - 150 \degrees} | c = }} {{eqn | r = \cos 150 \degrees | c = [[Cosine of Conjugate Angle]] }} {{eqn | r = -\frac {\sqrt 3} 2 | c = [[Cosine of 150 Degrees|Cosine of $150 \degrees$]] }} {{end-eqn}} {{qed}}
Cosine of 210 Degrees
https://proofwiki.org/wiki/Cosine_of_210_Degrees
https://proofwiki.org/wiki/Cosine_of_210_Degrees
[ "Cosine Function" ]
[]
[ "Cosine of Conjugate Angle", "Cosine of 150 Degrees" ]
proofwiki-7953
Cosine of 225 Degrees
:$\cos 225 \degrees = \cos \dfrac {5 \pi} 4 = -\dfrac {\sqrt 2} 2$
{{begin-eqn}} {{eqn | l = \cos 225 \degrees | r = \map \cos {360 \degrees - 135 \degrees} | c = }} {{eqn | r = \cos 135 \degrees | c = Cosine of Conjugate Angle }} {{eqn | r = -\frac {\sqrt 2} 2 | c = Cosine of $135 \degrees$ }} {{end-eqn}} {{qed}}
:$\cos 225 \degrees = \cos \dfrac {5 \pi} 4 = -\dfrac {\sqrt 2} 2$
{{begin-eqn}} {{eqn | l = \cos 225 \degrees | r = \map \cos {360 \degrees - 135 \degrees} | c = }} {{eqn | r = \cos 135 \degrees | c = [[Cosine of Conjugate Angle]] }} {{eqn | r = -\frac {\sqrt 2} 2 | c = [[Cosine of 135 Degrees|Cosine of $135 \degrees$]] }} {{end-eqn}} {{qed}}
Cosine of 225 Degrees
https://proofwiki.org/wiki/Cosine_of_225_Degrees
https://proofwiki.org/wiki/Cosine_of_225_Degrees
[ "Cosine Function" ]
[]
[ "Cosine of Conjugate Angle", "Cosine of 135 Degrees" ]
proofwiki-7954
Cosine of 240 Degrees
:$\cos 240 \degrees = \cos \dfrac {4 \pi} 3 = -\dfrac 1 2$
{{begin-eqn}} {{eqn | l = \cos 240 \degrees | r = \map \cos {360 \degrees - 120 \degrees} | c = }} {{eqn | r = \cos 120 \degrees | c = Cosine of Conjugate Angle }} {{eqn | r = -\frac 1 2 | c = Cosine of $120 \degrees$ }} {{end-eqn}} {{qed}}
:$\cos 240 \degrees = \cos \dfrac {4 \pi} 3 = -\dfrac 1 2$
{{begin-eqn}} {{eqn | l = \cos 240 \degrees | r = \map \cos {360 \degrees - 120 \degrees} | c = }} {{eqn | r = \cos 120 \degrees | c = [[Cosine of Conjugate Angle]] }} {{eqn | r = -\frac 1 2 | c = [[Cosine of 120 Degrees|Cosine of $120 \degrees$]] }} {{end-eqn}} {{qed}}
Cosine of 240 Degrees
https://proofwiki.org/wiki/Cosine_of_240_Degrees
https://proofwiki.org/wiki/Cosine_of_240_Degrees
[ "Cosine Function" ]
[]
[ "Cosine of Conjugate Angle", "Cosine of 120 Degrees" ]
proofwiki-7955
Cosine of 255 Degrees
:$\cos 255^\circ = \cos \dfrac {17 \pi} {12} = - \dfrac {\sqrt 6 - \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \cos 255^\circ | r = \cos \left({360^\circ - 105^\circ}\right) | c = }} {{eqn | r = \cos 105^\circ | c = Cosine of Conjugate Angle }} {{eqn | r = - \frac {\sqrt 6 - \sqrt 2} 4 | c = Cosine of 105 Degrees }} {{end-eqn}} {{qed}}
:$\cos 255^\circ = \cos \dfrac {17 \pi} {12} = - \dfrac {\sqrt 6 - \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \cos 255^\circ | r = \cos \left({360^\circ - 105^\circ}\right) | c = }} {{eqn | r = \cos 105^\circ | c = [[Cosine of Conjugate Angle]] }} {{eqn | r = - \frac {\sqrt 6 - \sqrt 2} 4 | c = [[Cosine of 105 Degrees]] }} {{end-eqn}} {{qed}}
Cosine of 255 Degrees
https://proofwiki.org/wiki/Cosine_of_255_Degrees
https://proofwiki.org/wiki/Cosine_of_255_Degrees
[ "Cosine Function" ]
[]
[ "Cosine of Conjugate Angle", "Cosine of 105 Degrees" ]
proofwiki-7956
Cosine of Three Right Angles
:$\cos 270 \degrees = \cos \dfrac {3 \pi} 2 = 0$
{{begin-eqn}} {{eqn | l = \cos 270 \degrees | r = \map \cos {360 \degrees - 90 \degrees} | c = }} {{eqn | r = \cos 90 \degrees | c = Cosine of Conjugate Angle }} {{eqn | r = 0 | c = Cosine of Right Angle }} {{end-eqn}} {{qed}}
:$\cos 270 \degrees = \cos \dfrac {3 \pi} 2 = 0$
{{begin-eqn}} {{eqn | l = \cos 270 \degrees | r = \map \cos {360 \degrees - 90 \degrees} | c = }} {{eqn | r = \cos 90 \degrees | c = [[Cosine of Conjugate Angle]] }} {{eqn | r = 0 | c = [[Cosine of Right Angle]] }} {{end-eqn}} {{qed}}
Cosine of Three Right Angles
https://proofwiki.org/wiki/Cosine_of_Three_Right_Angles
https://proofwiki.org/wiki/Cosine_of_Three_Right_Angles
[ "Cosine Function" ]
[]
[ "Cosine of Conjugate Angle", "Cosine of Right Angle" ]
proofwiki-7957
Cosine of 285 Degrees
:$\cos 285^\circ = \cos \dfrac {19 \pi} {12} = \dfrac {\sqrt 6 - \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \cos 285^\circ | r = \cos \left({360^\circ - 75^\circ}\right) | c = }} {{eqn | r = \cos 75^\circ | c = Cosine of Conjugate Angle }} {{eqn | r = \frac {\sqrt 6 - \sqrt 2} 4 | c = Cosine of 75 Degrees }} {{end-eqn}} {{qed}}
:$\cos 285^\circ = \cos \dfrac {19 \pi} {12} = \dfrac {\sqrt 6 - \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \cos 285^\circ | r = \cos \left({360^\circ - 75^\circ}\right) | c = }} {{eqn | r = \cos 75^\circ | c = [[Cosine of Conjugate Angle]] }} {{eqn | r = \frac {\sqrt 6 - \sqrt 2} 4 | c = [[Cosine of 75 Degrees]] }} {{end-eqn}} {{qed}}
Cosine of 285 Degrees
https://proofwiki.org/wiki/Cosine_of_285_Degrees
https://proofwiki.org/wiki/Cosine_of_285_Degrees
[ "Cosine Function" ]
[]
[ "Cosine of Conjugate Angle", "Cosine of 75 Degrees" ]
proofwiki-7958
Cosine of 300 Degrees
:$\cos 300 \degrees = \cos \dfrac {5 \pi} 3 = \dfrac 1 2$
{{begin-eqn}} {{eqn | l = \cos 300 \degrees | r = \map \cos {360 \degrees - 60 \degrees} | c = }} {{eqn | r = \cos 60 \degrees | c = Cosine of Conjugate Angle }} {{eqn | r = \frac 1 2 | c = {{cos|60}} }} {{end-eqn}} {{qed}}
:$\cos 300 \degrees = \cos \dfrac {5 \pi} 3 = \dfrac 1 2$
{{begin-eqn}} {{eqn | l = \cos 300 \degrees | r = \map \cos {360 \degrees - 60 \degrees} | c = }} {{eqn | r = \cos 60 \degrees | c = [[Cosine of Conjugate Angle]] }} {{eqn | r = \frac 1 2 | c = {{cos|60}} }} {{end-eqn}} {{qed}}
Cosine of 300 Degrees
https://proofwiki.org/wiki/Cosine_of_300_Degrees
https://proofwiki.org/wiki/Cosine_of_300_Degrees
[ "Cosine Function" ]
[]
[ "Cosine of Conjugate Angle" ]
proofwiki-7959
Cosine of 315 Degrees
:$\cos 315 \degrees = \cos \dfrac {7 \pi} 4 = \dfrac {\sqrt 2} 2$
{{begin-eqn}} {{eqn | l = \cos 315 \degrees | r = \map \cos {360 \degrees - 45 \degrees} | c = }} {{eqn | r = \cos 45 \degrees | c = Cosine of Conjugate Angle }} {{eqn | r = \frac {\sqrt 2} 2 | c = Cosine of $45 \degrees$ }} {{end-eqn}} {{qed}}
:$\cos 315 \degrees = \cos \dfrac {7 \pi} 4 = \dfrac {\sqrt 2} 2$
{{begin-eqn}} {{eqn | l = \cos 315 \degrees | r = \map \cos {360 \degrees - 45 \degrees} | c = }} {{eqn | r = \cos 45 \degrees | c = [[Cosine of Conjugate Angle]] }} {{eqn | r = \frac {\sqrt 2} 2 | c = [[Cosine of 45 Degrees|Cosine of $45 \degrees$]] }} {{end-eqn}} {{qed}}
Cosine of 315 Degrees
https://proofwiki.org/wiki/Cosine_of_315_Degrees
https://proofwiki.org/wiki/Cosine_of_315_Degrees
[ "Cosine Function" ]
[]
[ "Cosine of Conjugate Angle", "Cosine of 45 Degrees" ]
proofwiki-7960
Cosine of 330 Degrees
:$\cos 330 \degrees = \cos \dfrac {11 \pi} 6 = \dfrac {\sqrt 3} 2$
{{begin-eqn}} {{eqn | l = \cos 330 \degrees | r = \map \cos {360 \degrees - 30 \degrees} | c = }} {{eqn | r = \cos 30 \degrees | c = Cosine of Conjugate Angle }} {{eqn | r = \frac {\sqrt 3} 2 | c = Cosine of $30 \degrees$ }} {{end-eqn}} {{qed}}
:$\cos 330 \degrees = \cos \dfrac {11 \pi} 6 = \dfrac {\sqrt 3} 2$
{{begin-eqn}} {{eqn | l = \cos 330 \degrees | r = \map \cos {360 \degrees - 30 \degrees} | c = }} {{eqn | r = \cos 30 \degrees | c = [[Cosine of Conjugate Angle]] }} {{eqn | r = \frac {\sqrt 3} 2 | c = [[Cosine of 30 Degrees|Cosine of $30 \degrees$]] }} {{end-eqn}} {{qed}}
Cosine of 330 Degrees
https://proofwiki.org/wiki/Cosine_of_330_Degrees
https://proofwiki.org/wiki/Cosine_of_330_Degrees
[ "Cosine Function" ]
[]
[ "Cosine of Conjugate Angle", "Cosine of 30 Degrees" ]
proofwiki-7961
Cosine of 345 Degrees
:$\cos 345 \degrees = \cos \dfrac {23 \pi} {12} = \dfrac {\sqrt 6 + \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \cos 345 \degrees | r = \map \cos {360 \degrees - 15 \degrees} | c = }} {{eqn | r = \cos 15 \degrees | c = Cosine of Conjugate Angle }} {{eqn | r = \frac {\sqrt 6 + \sqrt 2} 4 | c = Cosine of $15 \degrees$ }} {{end-eqn}} {{qed}}
:$\cos 345 \degrees = \cos \dfrac {23 \pi} {12} = \dfrac {\sqrt 6 + \sqrt 2} 4$
{{begin-eqn}} {{eqn | l = \cos 345 \degrees | r = \map \cos {360 \degrees - 15 \degrees} | c = }} {{eqn | r = \cos 15 \degrees | c = [[Cosine of Conjugate Angle]] }} {{eqn | r = \frac {\sqrt 6 + \sqrt 2} 4 | c = [[Cosine of 15 Degrees|Cosine of $15 \degrees$]] }} {{end-eqn}} {{qed}}
Cosine of 345 Degrees
https://proofwiki.org/wiki/Cosine_of_345_Degrees
https://proofwiki.org/wiki/Cosine_of_345_Degrees
[ "Cosine Function" ]
[]
[ "Cosine of Conjugate Angle", "Cosine of 15 Degrees" ]
proofwiki-7962
Cosine of Full Angle
:$\cos 360 \degrees = \cos 2 \pi = 1$
A direct implementation of Cosine of Multiple of Pi: :$\forall n \in \Z: \cos n \pi = \paren {-1}^n$ In this case, $n = 2$ and so: :$\cos 2 \pi = \paren {-1}^2 = 1$ {{qed}}
:$\cos 360 \degrees = \cos 2 \pi = 1$
A direct implementation of [[Cosine of Multiple of Pi]]: :$\forall n \in \Z: \cos n \pi = \paren {-1}^n$ In this case, $n = 2$ and so: :$\cos 2 \pi = \paren {-1}^2 = 1$ {{qed}}
Cosine of Full Angle
https://proofwiki.org/wiki/Cosine_of_Full_Angle
https://proofwiki.org/wiki/Cosine_of_Full_Angle
[ "Cosine Function" ]
[]
[ "Cosine of Integer Multiple of Pi" ]
proofwiki-7963
Tangent of Zero
:$\tan 0 = 0$
{{begin-eqn}} {{eqn | l = \tan 0 | r = \frac {\sin 0} {\cos 0} | c = Tangent is Sine divided by Cosine }} {{eqn | r = \frac 0 1 | c = Sine of Zero is Zero and Cosine of Zero is One }} {{eqn | r = 0 | c = }} {{end-eqn}} {{qed}}
:$\tan 0 = 0$
{{begin-eqn}} {{eqn | l = \tan 0 | r = \frac {\sin 0} {\cos 0} | c = [[Tangent is Sine divided by Cosine]] }} {{eqn | r = \frac 0 1 | c = [[Sine of Zero is Zero]] and [[Cosine of Zero is One]] }} {{eqn | r = 0 | c = }} {{end-eqn}} {{qed}}
Tangent of Zero
https://proofwiki.org/wiki/Tangent_of_Zero
https://proofwiki.org/wiki/Tangent_of_Zero
[ "Tangent Function" ]
[]
[ "Tangent is Sine divided by Cosine", "Sine of Zero is Zero", "Cosine of Zero is One" ]
proofwiki-7964
Tangent of 15 Degrees
:$\tan 15^\circ = \tan \dfrac {\pi} {12} = 2 - \sqrt 3$
{{begin-eqn}} {{eqn | l = \tan 15 \degrees | r = \tan \frac {30 \degrees} 2 | c = }} {{eqn | r = \frac {\sin 30 \degrees} {1 + \cos 30 \degrees} | c = {{Corollary|Half Angle Formula for Tangent|1}} }} {{eqn | r = \frac {\frac 1 2} {1 + \frac {\sqrt 3} 2} | c = {{sin|30}} and {{cos|30}} }} {{eqn...
:$\tan 15^\circ = \tan \dfrac {\pi} {12} = 2 - \sqrt 3$
{{begin-eqn}} {{eqn | l = \tan 15 \degrees | r = \tan \frac {30 \degrees} 2 | c = }} {{eqn | r = \frac {\sin 30 \degrees} {1 + \cos 30 \degrees} | c = {{Corollary|Half Angle Formula for Tangent|1}} }} {{eqn | r = \frac {\frac 1 2} {1 + \frac {\sqrt 3} 2} | c = {{sin|30}} and {{cos|30}} }} {{eqn...
Tangent of 15 Degrees/Proof 1
https://proofwiki.org/wiki/Tangent_of_15_Degrees
https://proofwiki.org/wiki/Tangent_of_15_Degrees/Proof_1
[ "Tangent of 15 Degrees", "Tangent Function" ]
[]
[ "Difference of Two Squares" ]
proofwiki-7965
Tangent of 15 Degrees
:$\tan 15^\circ = \tan \dfrac {\pi} {12} = 2 - \sqrt 3$
{{begin-eqn}} {{eqn | l = \tan 15 \degrees | r = \tan \frac {30 \degrees} 2 | c = }} {{eqn | r = \frac {1 - \cos 30 \degrees} {\sin 30 \degrees} | c = {{Corollary|Half Angle Formula for Tangent|2}} }} {{eqn | r = \frac {1 - \frac {\sqrt 3} 2} {\frac 1 2} | c = {{cos|30}} and {{sin|30}} }} {{eq...
:$\tan 15^\circ = \tan \dfrac {\pi} {12} = 2 - \sqrt 3$
{{begin-eqn}} {{eqn | l = \tan 15 \degrees | r = \tan \frac {30 \degrees} 2 | c = }} {{eqn | r = \frac {1 - \cos 30 \degrees} {\sin 30 \degrees} | c = {{Corollary|Half Angle Formula for Tangent|2}} }} {{eqn | r = \frac {1 - \frac {\sqrt 3} 2} {\frac 1 2} | c = {{cos|30}} and {{sin|30}} }} {{eq...
Tangent of 15 Degrees/Proof 2
https://proofwiki.org/wiki/Tangent_of_15_Degrees
https://proofwiki.org/wiki/Tangent_of_15_Degrees/Proof_2
[ "Tangent of 15 Degrees", "Tangent Function" ]
[]
[]
proofwiki-7966
Tangent of 15 Degrees
:$\tan 15^\circ = \tan \dfrac {\pi} {12} = 2 - \sqrt 3$
{{begin-eqn}} {{eqn | l = \tan 15 \degrees | r = \frac {\sin 15 \degrees} {\cos 15 \degrees} | c = Tangent is Sine divided by Cosine }} {{eqn | r = \frac {\frac {\sqrt 6 - \sqrt 2} 4} {\frac {\sqrt 6 + \sqrt 2} 4} | c = {{sin|15}} and {{cos|15}} }} {{eqn | r = \frac {\sqrt 6 - \sqrt 2} {\sqrt 6 + \sqr...
:$\tan 15^\circ = \tan \dfrac {\pi} {12} = 2 - \sqrt 3$
{{begin-eqn}} {{eqn | l = \tan 15 \degrees | r = \frac {\sin 15 \degrees} {\cos 15 \degrees} | c = [[Tangent is Sine divided by Cosine]] }} {{eqn | r = \frac {\frac {\sqrt 6 - \sqrt 2} 4} {\frac {\sqrt 6 + \sqrt 2} 4} | c = {{sin|15}} and {{cos|15}} }} {{eqn | r = \frac {\sqrt 6 - \sqrt 2} {\sqrt 6 + ...
Tangent of 15 Degrees/Proof 3
https://proofwiki.org/wiki/Tangent_of_15_Degrees
https://proofwiki.org/wiki/Tangent_of_15_Degrees/Proof_3
[ "Tangent of 15 Degrees", "Tangent Function" ]
[]
[ "Tangent is Sine divided by Cosine", "Definition:Fraction/Numerator", "Definition:Fraction/Denominator", "Difference of Two Squares", "Definition:Fraction/Numerator", "Definition:Fraction/Denominator" ]
proofwiki-7967
Tangent of 30 Degrees
:$\tan 30 \degrees = \tan \dfrac \pi 6 = \dfrac {\sqrt 3} 3$
{{begin-eqn}} {{eqn | l = \tan 30 \degrees | r = \frac {\sin 30 \degrees} {\cos 30 \degrees} | c = Tangent is Sine divided by Cosine }} {{eqn | r = \frac {\frac 1 2} {\frac {\sqrt 3} 2} | c = Sine of $30 \degrees$ and Cosine of $30 \degrees$ }} {{eqn | r = \frac 1 {\sqrt 3} | c = }} {{eqn | r =...
:$\tan 30 \degrees = \tan \dfrac \pi 6 = \dfrac {\sqrt 3} 3$
{{begin-eqn}} {{eqn | l = \tan 30 \degrees | r = \frac {\sin 30 \degrees} {\cos 30 \degrees} | c = [[Tangent is Sine divided by Cosine]] }} {{eqn | r = \frac {\frac 1 2} {\frac {\sqrt 3} 2} | c = [[Sine of 30 Degrees|Sine of $30 \degrees$]] and [[Cosine of 30 Degrees|Cosine of $30 \degrees$]] }} {{eqn...
Tangent of 30 Degrees
https://proofwiki.org/wiki/Tangent_of_30_Degrees
https://proofwiki.org/wiki/Tangent_of_30_Degrees
[ "Tangent of 30 Degrees", "Tangent Function" ]
[]
[ "Tangent is Sine divided by Cosine", "Sine of 30 Degrees", "Cosine of 30 Degrees" ]
proofwiki-7968
Tangent of 45 Degrees
:$\tan 45 \degrees = \tan \dfrac \pi 4 = 1$
{{begin-eqn}} {{eqn | l = \tan 45 \degrees | r = \frac {\sin 45 \degrees} {\cos 45 \degrees} | c = Tangent is Sine divided by Cosine }} {{eqn | r = \frac {\frac {\sqrt 2} 2} {\frac {\sqrt 2} 2} | c = Sine of $45 \degrees$ and Cosine of $45 \degrees$ }} {{eqn | r = 1 | c = dividing top and bottom...
:$\tan 45 \degrees = \tan \dfrac \pi 4 = 1$
{{begin-eqn}} {{eqn | l = \tan 45 \degrees | r = \frac {\sin 45 \degrees} {\cos 45 \degrees} | c = [[Tangent is Sine divided by Cosine]] }} {{eqn | r = \frac {\frac {\sqrt 2} 2} {\frac {\sqrt 2} 2} | c = [[Sine of 45 Degrees|Sine of $45 \degrees$]] and [[Cosine of 45 Degrees|Cosine of $45 \degrees$]] ...
Tangent of 45 Degrees
https://proofwiki.org/wiki/Tangent_of_45_Degrees
https://proofwiki.org/wiki/Tangent_of_45_Degrees
[ "Tangent Function" ]
[]
[ "Tangent is Sine divided by Cosine", "Sine of 45 Degrees", "Cosine of 45 Degrees" ]
proofwiki-7969
Tangent of 60 Degrees
:$\tan 60 \degrees = \tan \dfrac \pi 3 = \sqrt 3$
{{begin-eqn}} {{eqn | l = \tan 60 \degrees | r = \frac {\sin 60 \degrees} {\cos 60 \degrees} | c = Tangent is Sine divided by Cosine }} {{eqn | r = \frac {\frac {\sqrt 3} 2} {\frac 1 2} | c = Sine of $60 \degrees$ and Cosine of $60 \degrees$ }} {{eqn | r = \sqrt 3 | c = multiplying top and botto...
:$\tan 60 \degrees = \tan \dfrac \pi 3 = \sqrt 3$
{{begin-eqn}} {{eqn | l = \tan 60 \degrees | r = \frac {\sin 60 \degrees} {\cos 60 \degrees} | c = [[Tangent is Sine divided by Cosine]] }} {{eqn | r = \frac {\frac {\sqrt 3} 2} {\frac 1 2} | c = [[Sine of 60 Degrees|Sine of $60 \degrees$]] and [[Cosine of 60 Degrees|Cosine of $60 \degrees$]] }} {{eqn...
Tangent of 60 Degrees
https://proofwiki.org/wiki/Tangent_of_60_Degrees
https://proofwiki.org/wiki/Tangent_of_60_Degrees
[ "Tangent Function" ]
[]
[ "Tangent is Sine divided by Cosine", "Sine of 60 Degrees", "Cosine of 60 Degrees" ]
proofwiki-7970
Tangent of 75 Degrees
:$\tan 75 \degrees = \tan \dfrac {5 \pi} {12} = 2 + \sqrt 3$
{{begin-eqn}} {{eqn | l = \tan 75 \degrees | r = \frac {\sin 75 \degrees} {\cos 75 \degrees} | c = Tangent is Sine divided by Cosine }} {{eqn | r = \frac {\frac {\sqrt 6 + \sqrt 2} 4} {\frac {\sqrt 6 - \sqrt 2} 4} | c = {{sin|75}} and {{cos|75}} }} {{eqn | r = \frac {\sqrt 6 + \sqrt 2} {\sqrt 6 - \sqr...
:$\tan 75 \degrees = \tan \dfrac {5 \pi} {12} = 2 + \sqrt 3$
{{begin-eqn}} {{eqn | l = \tan 75 \degrees | r = \frac {\sin 75 \degrees} {\cos 75 \degrees} | c = [[Tangent is Sine divided by Cosine]] }} {{eqn | r = \frac {\frac {\sqrt 6 + \sqrt 2} 4} {\frac {\sqrt 6 - \sqrt 2} 4} | c = {{sin|75}} and {{cos|75}} }} {{eqn | r = \frac {\sqrt 6 + \sqrt 2} {\sqrt 6 - ...
Tangent of 75 Degrees
https://proofwiki.org/wiki/Tangent_of_75_Degrees
https://proofwiki.org/wiki/Tangent_of_75_Degrees
[ "Tangent Function" ]
[]
[ "Tangent is Sine divided by Cosine", "Definition:Fraction/Numerator", "Definition:Fraction/Denominator", "Difference of Two Squares", "Definition:Fraction/Numerator", "Definition:Fraction/Denominator" ]
proofwiki-7971
Tangent of Complement equals Cotangent
:$\map \tan {\dfrac \pi 2 - \theta} = \cot \theta$ for $\theta \ne n \pi$ where $\tan$ and $\cot$ are tangent and cotangent respectively. That is, the cotangent of an angle is the tangent of its complement. This relation is defined wherever $\sin \theta \ne 0$.
{{begin-eqn}} {{eqn | l = \map \tan {\frac \pi 2 - \theta} | r = \frac {\map \sin {\frac \pi 2 - \theta} } {\map \cos {\frac \pi 2 - \theta} } | c = Tangent is Sine divided by Cosine }} {{eqn | r = \frac {\cos \theta} {\sin \theta} | c = Sine and Cosine of Complementary Angles }} {{eqn | r = \cot \the...
:$\map \tan {\dfrac \pi 2 - \theta} = \cot \theta$ for $\theta \ne n \pi$ where $\tan$ and $\cot$ are [[Definition:Tangent Function|tangent]] and [[Definition:Cotangent|cotangent]] respectively. That is, the [[Definition:Cotangent|cotangent]] of an [[Definition:Angle|angle]] is the [[Definition:Tangent Function|tange...
{{begin-eqn}} {{eqn | l = \map \tan {\frac \pi 2 - \theta} | r = \frac {\map \sin {\frac \pi 2 - \theta} } {\map \cos {\frac \pi 2 - \theta} } | c = [[Tangent is Sine divided by Cosine]] }} {{eqn | r = \frac {\cos \theta} {\sin \theta} | c = [[Sine and Cosine of Complementary Angles]] }} {{eqn | r = \...
Tangent of Complement equals Cotangent
https://proofwiki.org/wiki/Tangent_of_Complement_equals_Cotangent
https://proofwiki.org/wiki/Tangent_of_Complement_equals_Cotangent
[ "Tangent Function", "Cotangent Function", "Complementary Angles" ]
[ "Definition:Tangent Function", "Definition:Cotangent", "Definition:Cotangent", "Definition:Angle", "Definition:Tangent Function", "Definition:Complementary Angles" ]
[ "Tangent is Sine divided by Cosine", "Sine and Cosine of Complementary Angles", "Cotangent is Cosine divided by Sine", "Sine of Integer Multiple of Pi" ]
proofwiki-7972
Cotangent of Complement equals Tangent
Let $\theta \ne \paren {2 n + 1} \dfrac \pi 2$ Then: :$\map \cot {\dfrac \pi 2 - \theta} = \tan \theta$
{{begin-eqn}} {{eqn | l = \map \cot {\frac \pi 2 - \theta} | r = \frac {\map \cos {\frac \pi 2 - \theta} } {\map \sin {\frac \pi 2 - \theta} } | c = Cotangent is Cosine divided by Sine }} {{eqn | r = \frac {\sin \theta} {\cos \theta} | c = Sine and Cosine of Complementary Angles }} {{eqn | r = \tan \t...
Let $\theta \ne \paren {2 n + 1} \dfrac \pi 2$ Then: :$\map \cot {\dfrac \pi 2 - \theta} = \tan \theta$
{{begin-eqn}} {{eqn | l = \map \cot {\frac \pi 2 - \theta} | r = \frac {\map \cos {\frac \pi 2 - \theta} } {\map \sin {\frac \pi 2 - \theta} } | c = [[Cotangent is Cosine divided by Sine]] }} {{eqn | r = \frac {\sin \theta} {\cos \theta} | c = [[Sine and Cosine of Complementary Angles]] }} {{eqn | r =...
Cotangent of Complement equals Tangent
https://proofwiki.org/wiki/Cotangent_of_Complement_equals_Tangent
https://proofwiki.org/wiki/Cotangent_of_Complement_equals_Tangent
[ "Cotangent of Complement equals Tangent", "Tangent Function", "Cotangent Function", "Complementary Angles" ]
[]
[ "Cotangent is Cosine divided by Sine", "Sine and Cosine of Complementary Angles", "Tangent is Sine divided by Cosine", "Cosine of Half-Integer Multiple of Pi" ]
proofwiki-7973
Tangent of Angle plus Right Angle
:$\map \tan {x + \dfrac \pi 2} = -\cot x$
{{begin-eqn}} {{eqn | l = \map \tan {x + \frac \pi 2} | r = \frac {\map \sin {x + \frac \pi 2} } {\map \cos {x + \frac \pi 2} } | c = Tangent is Sine divided by Cosine }} {{eqn | r = \frac {\cos x} {- \sin x} | c = Sine of Angle plus Right Angle and Cosine of Angle plus Right Angle }} {{eqn | r = -\c...
:$\map \tan {x + \dfrac \pi 2} = -\cot x$
{{begin-eqn}} {{eqn | l = \map \tan {x + \frac \pi 2} | r = \frac {\map \sin {x + \frac \pi 2} } {\map \cos {x + \frac \pi 2} } | c = [[Tangent is Sine divided by Cosine]] }} {{eqn | r = \frac {\cos x} {- \sin x} | c = [[Sine of Angle plus Right Angle]] and [[Cosine of Angle plus Right Angle]] }} {{e...
Tangent of Angle plus Right Angle
https://proofwiki.org/wiki/Tangent_of_Angle_plus_Right_Angle
https://proofwiki.org/wiki/Tangent_of_Angle_plus_Right_Angle
[ "Tangent Function", "Reduction Formulae (Trigonometry)" ]
[]
[ "Tangent is Sine divided by Cosine", "Sine of Angle plus Right Angle", "Cosine of Angle plus Right Angle", "Cotangent is Cosine divided by Sine" ]
proofwiki-7974
Cotangent of Angle plus Right Angle
:$\map \cot {x + \dfrac \pi 2} = -\tan x$
{{begin-eqn}} {{eqn | l = \map \cot {x + \frac \pi 2} | r = \frac {\map \cos {x + \frac \pi 2} } {\map \sin {x + \frac \pi 2} } | c = Cotangent is Cosine divided by Sine }} {{eqn | r = \frac {-\sin x} {\cos x} | c = Cosine of Angle plus Right Angle and Sine of Angle plus Right Angle }} {{eqn | r = -\...
:$\map \cot {x + \dfrac \pi 2} = -\tan x$
{{begin-eqn}} {{eqn | l = \map \cot {x + \frac \pi 2} | r = \frac {\map \cos {x + \frac \pi 2} } {\map \sin {x + \frac \pi 2} } | c = [[Cotangent is Cosine divided by Sine]] }} {{eqn | r = \frac {-\sin x} {\cos x} | c = [[Cosine of Angle plus Right Angle]] and [[Sine of Angle plus Right Angle]] }} {{...
Cotangent of Angle plus Right Angle
https://proofwiki.org/wiki/Cotangent_of_Angle_plus_Right_Angle
https://proofwiki.org/wiki/Cotangent_of_Angle_plus_Right_Angle
[ "Cotangent Function", "Reduction Formulae (Trigonometry)" ]
[]
[ "Cotangent is Cosine divided by Sine", "Cosine of Angle plus Right Angle", "Sine of Angle plus Right Angle", "Tangent is Sine divided by Cosine" ]
proofwiki-7975
Tangent of Supplementary Angle
:$\map \tan {\pi - \theta} = -\tan \theta$ where $\tan$ denotes tangent. That is, the tangent of an angle is the negative of its supplement.
{{begin-eqn}} {{eqn | l = \map \tan {\pi - \theta} | r = \frac {\map \sin {\pi - \theta} } {\map \cos {\pi - \theta} } | c = Tangent is Sine divided by Cosine }} {{eqn | r = \frac {\sin \theta} {-\cos \theta} | c = Sine of Supplementary Angle and Cosine of Supplementary Angle }} {{eqn | r = -\tan \the...
:$\map \tan {\pi - \theta} = -\tan \theta$ where $\tan$ denotes [[Definition:Tangent Function|tangent]]. That is, the [[Definition:Tangent Function|tangent]] of an [[Definition:Angle|angle]] is the negative of its [[Definition:Supplement of Angle|supplement]].
{{begin-eqn}} {{eqn | l = \map \tan {\pi - \theta} | r = \frac {\map \sin {\pi - \theta} } {\map \cos {\pi - \theta} } | c = [[Tangent is Sine divided by Cosine]] }} {{eqn | r = \frac {\sin \theta} {-\cos \theta} | c = [[Sine of Supplementary Angle]] and [[Cosine of Supplementary Angle]] }} {{eqn | r ...
Tangent of Supplementary Angle
https://proofwiki.org/wiki/Tangent_of_Supplementary_Angle
https://proofwiki.org/wiki/Tangent_of_Supplementary_Angle
[ "Tangent Function", "Supplementary Angles" ]
[ "Definition:Tangent Function", "Definition:Tangent Function", "Definition:Angle", "Definition:Supplementary Angles" ]
[ "Tangent is Sine divided by Cosine", "Sine of Supplementary Angle", "Cosine of Supplementary Angle" ]
proofwiki-7976
Cotangent of Supplementary Angle
:$\map \cot {\pi - \theta} = -\cot \theta$ where $\cot$ denotes tangent. That is, the cotangent of an angle is the negative of its supplement.
{{begin-eqn}} {{eqn | l = \map \cot {\pi - \theta} | r = \frac {\map \cos {\pi - \theta} } {\map \sin {\pi - \theta} } | c = Cotangent is Cosine divided by Sine }} {{eqn | r = \frac {-\cos \theta} {\sin \theta} | c = Cosine of Supplementary Angle and Sine of Supplementary Angle }} {{eqn | r = -\cot \...
:$\map \cot {\pi - \theta} = -\cot \theta$ where $\cot$ denotes [[Definition:Tangent Function|tangent]]. That is, the [[Definition:Cotangent|cotangent]] of an [[Definition:Angle|angle]] is the negative of its [[Definition:Supplement of Angle|supplement]].
{{begin-eqn}} {{eqn | l = \map \cot {\pi - \theta} | r = \frac {\map \cos {\pi - \theta} } {\map \sin {\pi - \theta} } | c = [[Cotangent is Cosine divided by Sine]] }} {{eqn | r = \frac {-\cos \theta} {\sin \theta} | c = [[Cosine of Supplementary Angle]] and [[Sine of Supplementary Angle]] }} {{eqn |...
Cotangent of Supplementary Angle
https://proofwiki.org/wiki/Cotangent_of_Supplementary_Angle
https://proofwiki.org/wiki/Cotangent_of_Supplementary_Angle
[ "Cotangent Function", "Supplementary Angles" ]
[ "Definition:Tangent Function", "Definition:Cotangent", "Definition:Angle", "Definition:Supplementary Angles" ]
[ "Cotangent is Cosine divided by Sine", "Cosine of Supplementary Angle", "Sine of Supplementary Angle" ]
proofwiki-7977
Tangent of Conjugate Angle
:$\map \tan {2 \pi - \theta} = -\tan \theta$ where $\tan$ denotes tangent. That is, the tangent of an angle is the negative of its conjugate.
{{begin-eqn}} {{eqn | l = \map \tan {2 \pi - \theta} | r = \frac {\map \sin {2 \pi - \theta} } {\map \cos {2 \pi - \theta} } | c = Tangent is Sine divided by Cosine }} {{eqn | r = \frac {-\sin \theta} {\cos \theta} | c = Sine of Conjugate Angle and Cosine of Conjugate Angle }} {{eqn | r = -\tan \theta...
:$\map \tan {2 \pi - \theta} = -\tan \theta$ where $\tan$ denotes [[Definition:Tangent Function|tangent]]. That is, the [[Definition:Tangent Function|tangent]] of an [[Definition:Angle|angle]] is the negative of its [[Definition:Conjugate Angle|conjugate]].
{{begin-eqn}} {{eqn | l = \map \tan {2 \pi - \theta} | r = \frac {\map \sin {2 \pi - \theta} } {\map \cos {2 \pi - \theta} } | c = [[Tangent is Sine divided by Cosine]] }} {{eqn | r = \frac {-\sin \theta} {\cos \theta} | c = [[Sine of Conjugate Angle]] and [[Cosine of Conjugate Angle]] }} {{eqn | r = ...
Tangent of Conjugate Angle
https://proofwiki.org/wiki/Tangent_of_Conjugate_Angle
https://proofwiki.org/wiki/Tangent_of_Conjugate_Angle
[ "Tangent Function", "Conjugate Angles" ]
[ "Definition:Tangent Function", "Definition:Tangent Function", "Definition:Angle", "Definition:Conjugate Angles" ]
[ "Tangent is Sine divided by Cosine", "Sine of Conjugate Angle", "Cosine of Conjugate Angle", "Tangent is Sine divided by Cosine" ]
proofwiki-7978
Cotangent of Conjugate Angle
:$\map \cot {2 \pi - \theta} = -\cot \theta$ where $\cot$ denotes cotangent. That is, the cotangent of an angle is the negative of its conjugate.
{{begin-eqn}} {{eqn | l = \map \cot {2 \pi - \theta} | r = \frac {\map \cos {2 \pi - \theta} } {\map \sin {2 \pi - \theta} } | c = Cotangent is Cosine divided by Sine }} {{eqn | r = \frac {\cos \theta} {-\sin \theta} | c = Cosine of Conjugate Angle and Sine of Conjugate Angle }} {{eqn | r = -\cot \the...
:$\map \cot {2 \pi - \theta} = -\cot \theta$ where $\cot$ denotes [[Definition:Cotangent|cotangent]]. That is, the [[Definition:Cotangent|cotangent]] of an [[Definition:Angle|angle]] is the negative of its [[Definition:Conjugate Angle|conjugate]].
{{begin-eqn}} {{eqn | l = \map \cot {2 \pi - \theta} | r = \frac {\map \cos {2 \pi - \theta} } {\map \sin {2 \pi - \theta} } | c = [[Cotangent is Cosine divided by Sine]] }} {{eqn | r = \frac {\cos \theta} {-\sin \theta} | c = [[Cosine of Conjugate Angle]] and [[Sine of Conjugate Angle]] }} {{eqn | r ...
Cotangent of Conjugate Angle
https://proofwiki.org/wiki/Cotangent_of_Conjugate_Angle
https://proofwiki.org/wiki/Cotangent_of_Conjugate_Angle
[ "Cotangent Function", "Conjugate Angles" ]
[ "Definition:Cotangent", "Definition:Cotangent", "Definition:Angle", "Definition:Conjugate Angles" ]
[ "Cotangent is Cosine divided by Sine", "Cosine of Conjugate Angle", "Sine of Conjugate Angle", "Cotangent is Cosine divided by Sine" ]
proofwiki-7979
Tangent of Right Angle
:$\tan 90 \degrees = \tan \dfrac \pi 2$ is undefined
From Tangent is Sine divided by Cosine: :$\tan \theta = \dfrac {\sin \theta} {\cos \theta}$ When $\cos \theta = 0$, $\dfrac {\sin \theta} {\cos \theta}$ can be defined only if $\sin \theta = 0$. But there are no such $\theta$ such that both $\cos \theta = 0$ and $\sin \theta = 0$. When $\theta = \dfrac \pi 2$, $\cos \t...
:$\tan 90 \degrees = \tan \dfrac \pi 2$ is undefined
From [[Tangent is Sine divided by Cosine]]: :$\tan \theta = \dfrac {\sin \theta} {\cos \theta}$ When $\cos \theta = 0$, $\dfrac {\sin \theta} {\cos \theta}$ can be defined only if $\sin \theta = 0$. But there are no such $\theta$ such that both $\cos \theta = 0$ and $\sin \theta = 0$. When $\theta = \dfrac \pi 2$, $...
Tangent of Right Angle
https://proofwiki.org/wiki/Tangent_of_Right_Angle
https://proofwiki.org/wiki/Tangent_of_Right_Angle
[ "Tangent Function" ]
[]
[ "Tangent is Sine divided by Cosine" ]
proofwiki-7980
Tangent of 105 Degrees
:$\tan 105^\circ = \tan \dfrac {7 \pi} {12} = - \left({2 + \sqrt 3}\right)$
{{begin-eqn}} {{eqn | l = \tan 105^\circ | r = \tan \left({90^\circ + 15^\circ}\right) | c = }} {{eqn | r = - \cot 15^\circ | c = Tangent of Angle plus Right Angle }} {{eqn | r = - \left({2 + \sqrt 3}\right) | c = Cotangent of 15 Degrees }} {{end-eqn}} {{qed}}
:$\tan 105^\circ = \tan \dfrac {7 \pi} {12} = - \left({2 + \sqrt 3}\right)$
{{begin-eqn}} {{eqn | l = \tan 105^\circ | r = \tan \left({90^\circ + 15^\circ}\right) | c = }} {{eqn | r = - \cot 15^\circ | c = [[Tangent of Angle plus Right Angle]] }} {{eqn | r = - \left({2 + \sqrt 3}\right) | c = [[Cotangent of 15 Degrees]] }} {{end-eqn}} {{qed}}
Tangent of 105 Degrees
https://proofwiki.org/wiki/Tangent_of_105_Degrees
https://proofwiki.org/wiki/Tangent_of_105_Degrees
[ "Tangent Function" ]
[]
[ "Tangent of Angle plus Right Angle", "Cotangent of 15 Degrees" ]
proofwiki-7981
Tangent of 120 Degrees
:$\tan 120 \degrees = \tan \dfrac {2 \pi} 3 = -\sqrt 3$
{{begin-eqn}} {{eqn | l = \tan 120 \degrees | r = \map \tan {90 \degrees + 30 \degrees} | c = }} {{eqn | r = -\cot 30 \degrees | c = Tangent of Angle plus Right Angle }} {{eqn | r = -\sqrt 3 | c = Cotangent of $30 \degrees$ }} {{end-eqn}} {{qed}}
:$\tan 120 \degrees = \tan \dfrac {2 \pi} 3 = -\sqrt 3$
{{begin-eqn}} {{eqn | l = \tan 120 \degrees | r = \map \tan {90 \degrees + 30 \degrees} | c = }} {{eqn | r = -\cot 30 \degrees | c = [[Tangent of Angle plus Right Angle]] }} {{eqn | r = -\sqrt 3 | c = [[Cotangent of 30 Degrees|Cotangent of $30 \degrees$]] }} {{end-eqn}} {{qed}}
Tangent of 120 Degrees
https://proofwiki.org/wiki/Tangent_of_120_Degrees
https://proofwiki.org/wiki/Tangent_of_120_Degrees
[ "Tangent Function" ]
[]
[ "Tangent of Angle plus Right Angle", "Cotangent of 30 Degrees" ]
proofwiki-7982
Tangent of 135 Degrees
:$\tan 135^\circ = \tan \dfrac {3 \pi} 4 = - 1$
{{begin-eqn}} {{eqn | l = \tan 135^\circ | r = \tan \left({90^\circ + 45^\circ}\right) | c = }} {{eqn | r = - \cot 45^\circ | c = Tangent of Angle plus Right Angle }} {{eqn | r = - 1 | c = Cotangent of 45 Degrees }} {{end-eqn}} {{qed}}
:$\tan 135^\circ = \tan \dfrac {3 \pi} 4 = - 1$
{{begin-eqn}} {{eqn | l = \tan 135^\circ | r = \tan \left({90^\circ + 45^\circ}\right) | c = }} {{eqn | r = - \cot 45^\circ | c = [[Tangent of Angle plus Right Angle]] }} {{eqn | r = - 1 | c = [[Cotangent of 45 Degrees]] }} {{end-eqn}} {{qed}}
Tangent of 135 Degrees
https://proofwiki.org/wiki/Tangent_of_135_Degrees
https://proofwiki.org/wiki/Tangent_of_135_Degrees
[ "Tangent Function" ]
[]
[ "Tangent of Angle plus Right Angle", "Cotangent of 45 Degrees" ]
proofwiki-7983
Tangent of 150 Degrees
:$\tan 150 \degrees = \tan \dfrac {5 \pi} 6 = -\dfrac {\sqrt 3} 3$
{{begin-eqn}} {{eqn | l = \tan 150 \degrees | r = \map \tan {90 \degrees + 60 \degrees} | c = }} {{eqn | r = -\cot 60 \degrees | c = Tangent of Angle plus Right Angle }} {{eqn | r = -\dfrac {\sqrt 3} 3 | c = Cotangent of $60 \degrees$ }} {{end-eqn}} {{qed}}
:$\tan 150 \degrees = \tan \dfrac {5 \pi} 6 = -\dfrac {\sqrt 3} 3$
{{begin-eqn}} {{eqn | l = \tan 150 \degrees | r = \map \tan {90 \degrees + 60 \degrees} | c = }} {{eqn | r = -\cot 60 \degrees | c = [[Tangent of Angle plus Right Angle]] }} {{eqn | r = -\dfrac {\sqrt 3} 3 | c = [[Cotangent of 60 Degrees|Cotangent of $60 \degrees$]] }} {{end-eqn}} {{qed}}
Tangent of 150 Degrees
https://proofwiki.org/wiki/Tangent_of_150_Degrees
https://proofwiki.org/wiki/Tangent_of_150_Degrees
[ "Tangent Function" ]
[]
[ "Tangent of Angle plus Right Angle", "Cotangent of 60 Degrees" ]
proofwiki-7984
Tangent of 165 Degrees
:$\tan 165 \degrees = \tan \dfrac {11 \pi} {12} = -\paren {2 - \sqrt 3}$
{{begin-eqn}} {{eqn | l = \tan 165 \degrees | r = \map \tan {90 \degrees + 75 \degrees} | c = }} {{eqn | r = -\cot 75 \degrees | c = Tangent of Angle plus Right Angle }} {{eqn | r = -\paren {2 - \sqrt 3} | c = Cotangent of $75 \degrees$ }} {{end-eqn}} {{qed}}
:$\tan 165 \degrees = \tan \dfrac {11 \pi} {12} = -\paren {2 - \sqrt 3}$
{{begin-eqn}} {{eqn | l = \tan 165 \degrees | r = \map \tan {90 \degrees + 75 \degrees} | c = }} {{eqn | r = -\cot 75 \degrees | c = [[Tangent of Angle plus Right Angle]] }} {{eqn | r = -\paren {2 - \sqrt 3} | c = [[Cotangent of 75 Degrees|Cotangent of $75 \degrees$]] }} {{end-eqn}} {{qed}}
Tangent of 165 Degrees
https://proofwiki.org/wiki/Tangent_of_165_Degrees
https://proofwiki.org/wiki/Tangent_of_165_Degrees
[ "Tangent Function" ]
[]
[ "Tangent of Angle plus Right Angle", "Cotangent of 75 Degrees" ]
proofwiki-7985
Tangent of Straight Angle
:$\tan 180 \degrees = \tan \pi = 0$
{{begin-eqn}} {{eqn | l = \tan 180 \degrees | r = \frac {\sin 180 \degrees} {\cos 180 \degrees} | c = Tangent is Sine divided by Cosine }} {{eqn | r = \frac 0 {-1} | c = Sine of Straight Angle and Cosine of Straight Angle }} {{eqn | r = 0 | c = }} {{end-eqn}} {{qed}}
:$\tan 180 \degrees = \tan \pi = 0$
{{begin-eqn}} {{eqn | l = \tan 180 \degrees | r = \frac {\sin 180 \degrees} {\cos 180 \degrees} | c = [[Tangent is Sine divided by Cosine]] }} {{eqn | r = \frac 0 {-1} | c = [[Sine of Straight Angle]] and [[Cosine of Straight Angle]] }} {{eqn | r = 0 | c = }} {{end-eqn}} {{qed}}
Tangent of Straight Angle
https://proofwiki.org/wiki/Tangent_of_Straight_Angle
https://proofwiki.org/wiki/Tangent_of_Straight_Angle
[ "Tangent Function" ]
[]
[ "Tangent is Sine divided by Cosine", "Sine of Straight Angle", "Cosine of Straight Angle" ]
proofwiki-7986
Tangent of 195 Degrees
:$\tan 195 \degrees = \tan \dfrac {13 \pi} {12} = 2 - \sqrt 3$
{{begin-eqn}} {{eqn | l = \tan 195 \degrees | r = \map \tan {360 \degrees - 165 \degrees} | c = }} {{eqn | r = -\tan 165 \degrees | c = Tangent of Conjugate Angle }} {{eqn | r = 2 - \sqrt 3 | c = Tangent of $165 \degrees$ }} {{end-eqn}} {{qed}}
:$\tan 195 \degrees = \tan \dfrac {13 \pi} {12} = 2 - \sqrt 3$
{{begin-eqn}} {{eqn | l = \tan 195 \degrees | r = \map \tan {360 \degrees - 165 \degrees} | c = }} {{eqn | r = -\tan 165 \degrees | c = [[Tangent of Conjugate Angle]] }} {{eqn | r = 2 - \sqrt 3 | c = [[Tangent of 165 Degrees|Tangent of $165 \degrees$]] }} {{end-eqn}} {{qed}}
Tangent of 195 Degrees
https://proofwiki.org/wiki/Tangent_of_195_Degrees
https://proofwiki.org/wiki/Tangent_of_195_Degrees
[ "Tangent Function" ]
[]
[ "Tangent of Conjugate Angle", "Tangent of 165 Degrees" ]
proofwiki-7987
Tangent of 210 Degrees
:$\tan 210 \degrees = \tan \dfrac {7 \pi} 6 = \dfrac {\sqrt 3} 3$
{{begin-eqn}} {{eqn | l = \tan 210 \degrees | r = \map \tan {360 \degrees - 150 \degrees} | c = }} {{eqn | r = -\tan 150 \degrees | c = Tangent of Conjugate Angle }} {{eqn | r = \frac {\sqrt 3} 3 | c = Tangent of $150 \degrees$ }} {{end-eqn}} {{qed}}
:$\tan 210 \degrees = \tan \dfrac {7 \pi} 6 = \dfrac {\sqrt 3} 3$
{{begin-eqn}} {{eqn | l = \tan 210 \degrees | r = \map \tan {360 \degrees - 150 \degrees} | c = }} {{eqn | r = -\tan 150 \degrees | c = [[Tangent of Conjugate Angle]] }} {{eqn | r = \frac {\sqrt 3} 3 | c = [[Tangent of 150 Degrees|Tangent of $150 \degrees$]] }} {{end-eqn}} {{qed}}
Tangent of 210 Degrees
https://proofwiki.org/wiki/Tangent_of_210_Degrees
https://proofwiki.org/wiki/Tangent_of_210_Degrees
[ "Tangent Function" ]
[]
[ "Tangent of Conjugate Angle", "Tangent of 150 Degrees" ]
proofwiki-7988
Tangent of 225 Degrees
:$\tan 225 \degrees = \tan \dfrac {5 \pi} 4 = 1$
{{begin-eqn}} {{eqn | l = \tan 225 \degrees | r = \map \tan {360 \degrees - 135 \degrees} | c = }} {{eqn | r = -\tan 135 \degrees | c = Tangent of Conjugate Angle }} {{eqn | r = 1 | c = {{tan|135}} }} {{end-eqn}} {{qed}}
:$\tan 225 \degrees = \tan \dfrac {5 \pi} 4 = 1$
{{begin-eqn}} {{eqn | l = \tan 225 \degrees | r = \map \tan {360 \degrees - 135 \degrees} | c = }} {{eqn | r = -\tan 135 \degrees | c = [[Tangent of Conjugate Angle]] }} {{eqn | r = 1 | c = {{tan|135}} }} {{end-eqn}} {{qed}}
Tangent of 225 Degrees
https://proofwiki.org/wiki/Tangent_of_225_Degrees
https://proofwiki.org/wiki/Tangent_of_225_Degrees
[ "Tangent Function" ]
[]
[ "Tangent of Conjugate Angle" ]
proofwiki-7989
Tangent of 240 Degrees
:$\tan 240 \degrees = \tan \dfrac {4 \pi} 3 = \sqrt 3$
{{begin-eqn}} {{eqn | l = \tan 240 \degrees | r = \map \tan {360 \degrees - 120 \degrees} | c = }} {{eqn | r = -\tan 120 \degrees | c = Tangent of Conjugate Angle }} {{eqn | r = \sqrt 3 | c = Tangent of $120 \degrees$ }} {{end-eqn}} {{qed}}
:$\tan 240 \degrees = \tan \dfrac {4 \pi} 3 = \sqrt 3$
{{begin-eqn}} {{eqn | l = \tan 240 \degrees | r = \map \tan {360 \degrees - 120 \degrees} | c = }} {{eqn | r = -\tan 120 \degrees | c = [[Tangent of Conjugate Angle]] }} {{eqn | r = \sqrt 3 | c = [[Tangent of 120 Degrees|Tangent of $120 \degrees$]] }} {{end-eqn}} {{qed}}
Tangent of 240 Degrees
https://proofwiki.org/wiki/Tangent_of_240_Degrees
https://proofwiki.org/wiki/Tangent_of_240_Degrees
[ "Tangent Function" ]
[]
[ "Tangent of Conjugate Angle", "Tangent of 120 Degrees" ]
proofwiki-7990
Tangent of 255 Degrees
:$\tan 255 \degrees = \tan \dfrac {17 \pi} {12} = 2 + \sqrt 3$
{{begin-eqn}} {{eqn | l = \tan 255 \degrees | r = \map \tan {360 \degrees - 105 \degrees} | c = }} {{eqn | r = -\tan 105 \degrees | c = Tangent of Conjugate Angle }} {{eqn | r = 2 + \sqrt 3 | c = Tangent of $105 \degrees$ }} {{end-eqn}} {{qed}}
:$\tan 255 \degrees = \tan \dfrac {17 \pi} {12} = 2 + \sqrt 3$
{{begin-eqn}} {{eqn | l = \tan 255 \degrees | r = \map \tan {360 \degrees - 105 \degrees} | c = }} {{eqn | r = -\tan 105 \degrees | c = [[Tangent of Conjugate Angle]] }} {{eqn | r = 2 + \sqrt 3 | c = [[Tangent of 105 Degrees|Tangent of $105 \degrees$]] }} {{end-eqn}} {{qed}}
Tangent of 255 Degrees
https://proofwiki.org/wiki/Tangent_of_255_Degrees
https://proofwiki.org/wiki/Tangent_of_255_Degrees
[ "Tangent Function" ]
[]
[ "Tangent of Conjugate Angle", "Tangent of 105 Degrees" ]
proofwiki-7991
Tangent of Three Right Angles
:$\tan 270 \degrees = \tan \dfrac {3 \pi} 2$ is undefined
We have: {{begin-eqn}} {{eqn | l = \tan 270 \degrees | r = \map \tan {360 \degrees - 90 \degrees} | c = }} {{eqn | r = -\tan 90 \degrees | c = Tangent of Conjugate Angle }} {{end-eqn}} But from Tangent of Right Angle, $\tan 90 \degrees$ is undefined. Hence so is $\tan 270 \degrees$. {{qed}}
:$\tan 270 \degrees = \tan \dfrac {3 \pi} 2$ is undefined
We have: {{begin-eqn}} {{eqn | l = \tan 270 \degrees | r = \map \tan {360 \degrees - 90 \degrees} | c = }} {{eqn | r = -\tan 90 \degrees | c = [[Tangent of Conjugate Angle]] }} {{end-eqn}} But from [[Tangent of Right Angle]], $\tan 90 \degrees$ is undefined. Hence so is $\tan 270 \degrees$. {{qed}}
Tangent of Three Right Angles
https://proofwiki.org/wiki/Tangent_of_Three_Right_Angles
https://proofwiki.org/wiki/Tangent_of_Three_Right_Angles
[ "Tangent Function" ]
[]
[ "Tangent of Conjugate Angle", "Tangent of Right Angle" ]
proofwiki-7992
Tangent of 285 Degrees
:$\tan 285 \degrees = \tan \dfrac {19 \pi} {12} = -\paren {2 + \sqrt 3}$
{{begin-eqn}} {{eqn | l = \tan 285 \degrees | r = \map \tan {360 \degrees - 75 \degrees} | c = }} {{eqn | r = -\tan 75 \degrees | c = Tangent of Conjugate Angle }} {{eqn | r = -\paren {2 + \sqrt 3} | c = Tangent of $75 \degrees$ }} {{end-eqn}} {{qed}}
:$\tan 285 \degrees = \tan \dfrac {19 \pi} {12} = -\paren {2 + \sqrt 3}$
{{begin-eqn}} {{eqn | l = \tan 285 \degrees | r = \map \tan {360 \degrees - 75 \degrees} | c = }} {{eqn | r = -\tan 75 \degrees | c = [[Tangent of Conjugate Angle]] }} {{eqn | r = -\paren {2 + \sqrt 3} | c = [[Tangent of 75 Degrees|Tangent of $75 \degrees$]] }} {{end-eqn}} {{qed}}
Tangent of 285 Degrees
https://proofwiki.org/wiki/Tangent_of_285_Degrees
https://proofwiki.org/wiki/Tangent_of_285_Degrees
[ "Tangent Function" ]
[]
[ "Tangent of Conjugate Angle", "Tangent of 75 Degrees" ]
proofwiki-7993
Tangent of 300 Degrees
:$\tan 300 \degrees = \tan \dfrac {5 \pi} 3 = -\sqrt 3$
{{begin-eqn}} {{eqn | l = \tan 300 \degrees | r = \map \tan {360 \degrees - 60 \degrees} | c = }} {{eqn | r = -\tan 60 \degrees | c = Tangent of Conjugate Angle }} {{eqn | r = -\sqrt 3 | c = Tangent of $60 \degrees$ }} {{end-eqn}} {{qed}}
:$\tan 300 \degrees = \tan \dfrac {5 \pi} 3 = -\sqrt 3$
{{begin-eqn}} {{eqn | l = \tan 300 \degrees | r = \map \tan {360 \degrees - 60 \degrees} | c = }} {{eqn | r = -\tan 60 \degrees | c = [[Tangent of Conjugate Angle]] }} {{eqn | r = -\sqrt 3 | c = [[Tangent of 60 Degrees|Tangent of $60 \degrees$]] }} {{end-eqn}} {{qed}}
Tangent of 300 Degrees
https://proofwiki.org/wiki/Tangent_of_300_Degrees
https://proofwiki.org/wiki/Tangent_of_300_Degrees
[ "Tangent Function" ]
[]
[ "Tangent of Conjugate Angle", "Tangent of 60 Degrees" ]
proofwiki-7994
Tangent of 315 Degrees
:$\tan 315 \degrees = \tan \dfrac {7 \pi} 4 = -1$
{{begin-eqn}} {{eqn | l = \tan 315 \degrees | r = \map \tan {360 \degrees - 45 \degrees} | c = }} {{eqn | r = -\tan 45 \degrees | c = Tangent of Conjugate Angle }} {{eqn | r = -1 | c = Tangent of $45 \degrees$ }} {{end-eqn}} {{qed}}
:$\tan 315 \degrees = \tan \dfrac {7 \pi} 4 = -1$
{{begin-eqn}} {{eqn | l = \tan 315 \degrees | r = \map \tan {360 \degrees - 45 \degrees} | c = }} {{eqn | r = -\tan 45 \degrees | c = [[Tangent of Conjugate Angle]] }} {{eqn | r = -1 | c = [[Tangent of 45 Degrees|Tangent of $45 \degrees$]] }} {{end-eqn}} {{qed}}
Tangent of 315 Degrees
https://proofwiki.org/wiki/Tangent_of_315_Degrees
https://proofwiki.org/wiki/Tangent_of_315_Degrees
[ "Tangent Function" ]
[]
[ "Tangent of Conjugate Angle", "Tangent of 45 Degrees" ]
proofwiki-7995
Tangent of 330 Degrees
:$\tan 330^\circ = \tan \dfrac {11 \pi} 6 = -\dfrac {\sqrt 3} 3$
{{begin-eqn}} {{eqn | l = \tan 330^\circ | r = \tan \left({360^\circ - 30^\circ}\right) | c = }} {{eqn | r = -\tan 30^\circ | c = Tangent of Conjugate Angle }} {{eqn | r = -\frac {\sqrt 3} 3 | c = Tangent of 30 Degrees }} {{end-eqn}} {{qed}}
:$\tan 330^\circ = \tan \dfrac {11 \pi} 6 = -\dfrac {\sqrt 3} 3$
{{begin-eqn}} {{eqn | l = \tan 330^\circ | r = \tan \left({360^\circ - 30^\circ}\right) | c = }} {{eqn | r = -\tan 30^\circ | c = [[Tangent of Conjugate Angle]] }} {{eqn | r = -\frac {\sqrt 3} 3 | c = [[Tangent of 30 Degrees]] }} {{end-eqn}} {{qed}}
Tangent of 330 Degrees
https://proofwiki.org/wiki/Tangent_of_330_Degrees
https://proofwiki.org/wiki/Tangent_of_330_Degrees
[ "Tangent Function" ]
[]
[ "Tangent of Conjugate Angle", "Tangent of 30 Degrees" ]
proofwiki-7996
Tangent of 345 Degrees
:$\tan 345^\circ = \tan \dfrac {23 \pi} {12} = -\left({2 - \sqrt 3}\right)$
{{begin-eqn}} {{eqn | l = \tan 345^\circ | r = \tan \left({360^\circ - 15^\circ}\right) | c = }} {{eqn | r = -\tan 15^\circ | c = Tangent of Conjugate Angle }} {{eqn | r = -\left({2 - \sqrt 3}\right) | c = Tangent of 15 Degrees }} {{end-eqn}} {{qed}}
:$\tan 345^\circ = \tan \dfrac {23 \pi} {12} = -\left({2 - \sqrt 3}\right)$
{{begin-eqn}} {{eqn | l = \tan 345^\circ | r = \tan \left({360^\circ - 15^\circ}\right) | c = }} {{eqn | r = -\tan 15^\circ | c = [[Tangent of Conjugate Angle]] }} {{eqn | r = -\left({2 - \sqrt 3}\right) | c = [[Tangent of 15 Degrees]] }} {{end-eqn}} {{qed}}
Tangent of 345 Degrees
https://proofwiki.org/wiki/Tangent_of_345_Degrees
https://proofwiki.org/wiki/Tangent_of_345_Degrees
[ "Tangent Function" ]
[]
[ "Tangent of Conjugate Angle", "Tangent of 15 Degrees" ]
proofwiki-7997
Tangent of Full Angle
:$\tan 360^\circ = \tan 2 \pi = 0$
{{begin-eqn}} {{eqn | l = \tan 360^\circ | r = \tan \left({360^\circ - 0^\circ}\right) | c = }} {{eqn | r = -\tan 0 | c = Tangent of Conjugate Angle }} {{eqn | r = 0 | c = Tangent of Zero }} {{end-eqn}} {{qed}}
:$\tan 360^\circ = \tan 2 \pi = 0$
{{begin-eqn}} {{eqn | l = \tan 360^\circ | r = \tan \left({360^\circ - 0^\circ}\right) | c = }} {{eqn | r = -\tan 0 | c = [[Tangent of Conjugate Angle]] }} {{eqn | r = 0 | c = [[Tangent of Zero]] }} {{end-eqn}} {{qed}}
Tangent of Full Angle
https://proofwiki.org/wiki/Tangent_of_Full_Angle
https://proofwiki.org/wiki/Tangent_of_Full_Angle
[ "Tangent Function" ]
[]
[ "Tangent of Conjugate Angle", "Tangent of Zero" ]
proofwiki-7998
Cotangent of Zero
:$\cot 0$ is undefined
From Cotangent is Cosine divided by Sine: :$\cot \theta = \dfrac {\cos \theta} {\sin \theta}$ When $\sin \theta = 0$, $\dfrac {\cos \theta} {\sin \theta}$ can be defined only if $\cos \theta = 0$. But there are no such $\theta$ such that both $\cos \theta = 0$ and $\sin \theta = 0$. When $\theta = 0$, $\sin \theta = 0$...
:$\cot 0$ is undefined
From [[Cotangent is Cosine divided by Sine]]: :$\cot \theta = \dfrac {\cos \theta} {\sin \theta}$ When $\sin \theta = 0$, $\dfrac {\cos \theta} {\sin \theta}$ can be defined only if $\cos \theta = 0$. But there are no such $\theta$ such that both $\cos \theta = 0$ and $\sin \theta = 0$. When $\theta = 0$, $\sin \the...
Cotangent of Zero
https://proofwiki.org/wiki/Cotangent_of_Zero
https://proofwiki.org/wiki/Cotangent_of_Zero
[ "Cotangent Function" ]
[]
[ "Cotangent is Cosine divided by Sine" ]
proofwiki-7999
Cotangent of 30 Degrees
:$\cot 30 \degrees = \cot \dfrac \pi 6 = \sqrt 3$
{{begin-eqn}} {{eqn | l = \cot 30 \degrees | r = \frac {\cos 30 \degrees} {\sin 30 \degrees} | c = Cotangent is Cosine divided by Sine }} {{eqn | r = \frac {\frac {\sqrt 3} 2} {\frac 1 2} | c = {{cos|30}} and {{sin|30}} }} {{eqn | r = \sqrt 3 | c = multiplying top and bottom by $2$ }} {{end-eqn...
:$\cot 30 \degrees = \cot \dfrac \pi 6 = \sqrt 3$
{{begin-eqn}} {{eqn | l = \cot 30 \degrees | r = \frac {\cos 30 \degrees} {\sin 30 \degrees} | c = [[Cotangent is Cosine divided by Sine]] }} {{eqn | r = \frac {\frac {\sqrt 3} 2} {\frac 1 2} | c = {{cos|30}} and {{sin|30}} }} {{eqn | r = \sqrt 3 | c = multiplying [[Definition:Numerator|top]] a...
Cotangent of 30 Degrees
https://proofwiki.org/wiki/Cotangent_of_30_Degrees
https://proofwiki.org/wiki/Cotangent_of_30_Degrees
[ "Cotangent Function" ]
[]
[ "Cotangent is Cosine divided by Sine", "Definition:Fraction/Numerator", "Definition:Fraction/Denominator" ]