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int64
5
895
Given the universal set $M=\{1,m,3+(m^{2}-5m-6)i\}$ and the set $N=\{x|x^{2}-2x-3=0\}$, if $M∩N=\{3\}$, find $M∪N$.
\{-1,1,3,3-12i\}
math
62
There exists a sequence of numbers $a_{1}$, $a_{2}$, $a_{3}$, $\ldots$, $a_{n}$, $\ldots$ that satisfies the following conditions: $a_{1}=\frac{1}{2}$, $a_{n}=\frac{1}{1-{a}_{n-1}}$ (for $n\geqslant 2$ and $n$ is an integer). Find:<br/> $(1) a_{2}=$______;<br/> $(2) a_{1}+a_{2}+a_{3}+\ldots +a_{2023}=\_\_\_\_\_\_$.
1011.5
math
149
Given two lines \( l_{1}: 2x + y = 3 \) and \( l_{2}: x + 4y = 2 \). The line \( l \) passes through the intersection point \( P \) of \( l_{1} \) and \( l_{2} \), as well as the origin. Find the equation of the line \( l \).
x - 10y = 0
math
81
In a crown, five diamonds are embedded at five positions, equally spaced around a circle. If there are three different colors of diamonds to choose from, how many different ways are there to embed the diamonds? Assume that the five positions are indistinguishable from each other.
51
math
54
The probability of A not losing is $\dfrac{1}{3} + \dfrac{1}{2}$.
\dfrac{1}{6}
math
25
Lines $p$ and $q$ are parallel. $m\angle E = 150^\circ$, and $m\angle G = 70^\circ$. What is the number of degrees in $m\angle F$? [asy] size(100); real h = 1.2; currentpen = fontsize(10pt); draw(Label("$p$",Relative(1)),(0,0)--(1,0),E); draw(Label("$q$",Relative(1)),(0,-h)--(1,-h),E); draw((0,-h)--h/2*(cos(150*pi/180...
110^\circ
math
289
Let α be in the interval $(-\frac{\pi}{2}, \frac{\pi}{2})$, and given that $\sin\alpha = -\frac{3}{5}$, find the value of $\cos(-\alpha)$.
\frac{4}{5}
math
51
Solve in $\mathbb{C}^{3}$ the system $$ \left\{\begin{array}{l} a^{2}+a b+c=0 \\ b^{2}+b c+a=0 \\ c^{2}+c a+b=0 \end{array}\right. $$
(0, 0, 0) \ \text{and} \ \left( -\frac{1}{2}, -\frac{1}{2}, -\frac{1}{2} \right)
math
68
Given a sequence $\{a_n\}$ with $a_1=1$ and $a_{n+1}= \frac{2a_n}{a_n+2}$, find the value of $a_{10}$.
\frac{2}{11}
math
49
Given that the function $f(x) = -x^3 + ax^2 - 4$ attains an extremum at $x = 2$, and if $m, n \in [-1,1]$, then the minimum value of $f(m) + f'(n)$ is ______.
-4 + (-9) = -13
math
64
Compute the sum $\frac{4}{3} + \frac{8}{9} + \frac{18}{27} + \frac{40}{81} + \frac{88}{243} - 5$. **A** $-\frac{1220}{972}$ **B** $-\frac{610}{486}$ **C** $-\frac{305}{243}$ **D** $-\frac{152.5}{121.5}$ **E** $-\frac{76.25}{60.75}$
-\frac{305}{243}
math
142
Given $\log 216$, evaluate the expression in terms of logarithms of prime factors.
3 \log 6
math
20
Determine the range of the function $f(x) = \log_{3}(8^{x}+1)$.
(0,\infty)
math
25
Given $\sin(x + \frac{\pi}{4}) = -\frac{3}{5}$, find the value of $\sin 2x$.
\frac{-7}{25}
math
32
Given the vectors $\overrightarrow{a}=(\cos x, \sin x)$, $\overrightarrow{b}=(\cos x + 2\sqrt{3}, \sin x)$, and $\overrightarrow{c}=(0, 1)$, where $x \in \mathbb{R}$: 1. If $\overrightarrow{a} \perp \overrightarrow{c}$, find the value of $\cos 2x$. 2. If the function $f(x) = \overrightarrow{a} \cdot (\overrightarrow{b}...
5
math
149
If $1998$ is written as a product of two positive integers whose difference is as small as possible, then the difference is
17
math
28
Given a line $l$ passes through point $P(2,3)$, and is intersected by two parallel lines $l_{1}: 3x+4y-7=0$ and $l_{2}: 3x+4y+8=0$ to form a line segment of length $d$. $(1)$ Find the minimum value of $d$; $(2)$ Calculate the value of $d$ when line $l$ is parallel to the x-axis.
5
math
103
What is the area of the region enclosed by the graph of the equation $x^2 - 20x + 5y + 100 = 25 + 15y - y^2$ that lies above the line $y = x - 6$?
25\pi
math
60
Given that $49$ of the first $50$ counted were red and $7$ out of every $8$ counted thereafter were red, find the maximum value of $n$, given that $90$% or more of the balls counted were red.
210
math
55
Given the arithmetic sequence $\{a_{n}\}$ with a common difference $d < 0$, let $S_{n}$ represent the sum of its first $n$ terms. It is known that $3 \sqrt {5}$ is the geometric mean between $-a_{2}$ and $a_{9}$, and $S_{10}=20$. Find the value of $d$.
d = -2
math
84
Define the sequence $(x_{n})$ : $x_{1}=\frac{1}{3}$ and $x_{n+1}=x_{n}^{2}+x_{n}$ . Find $\left[\frac{1}{x_{1}+1}+\frac{1}{x_{2}+1}+\dots+\frac{1}{x_{2007}+1}\right]$ , wehere $[$ $]$ denotes the integer part.
2
math
109
A group of 12 friends decides to form a committee of 5. Calculate the number of different committees that can be formed. Additionally, if there are 4 friends who refuse to work together, how many committees can be formed without any of these 4 friends?
56
math
55
A point $P$ lies in the same plane as a given square of side $2$. Let the vertices of the square, taken counterclockwise, be $A, B, C$ and $D$. Also, let the distances from $P$ to $B, C$ and $D$, respectively, be $v, w$ and $t$. What is the greatest distance that $P$ can be from $A$ if $v^2 + w^2 = t^2$? A) $\sqrt{8}$ ...
\sqrt{10}
math
139
The volume of the parallelepiped $A B C D A_1 B_1 C_1 D_1$ is $V$. Find the volume of the pyramid $A B C C_1$.
\frac{1}{6} V
math
43
What is the hundreds digit of $(25! - 20!)$?
0
math
17
How many positive cubes divide $3!\cdot 5!\cdot 7!\,$?
6
math
20
If $f(x) = x^2 + 2\int_{0}^{1}f(x)dx,$ then $\int_{0}^{1}f(x)dx=$
-\frac{1}{3}
math
39
Find all positive integers $n$ such that $1! + 2! + \ldots + n!$ is a perfect square.
1 \text{ and } 3
math
29
The "Tuning Day Method" is a procedural algorithm for seeking precise fractional representations of numbers. Suppose the insufficient approximation and the excessive approximation of a real number $x$ are $\dfrac{b}{a}$ and $\dfrac{d}{c}$ ($a,b,c,d \in \mathbb{N}^*$) respectively, then $\dfrac{b+d}{a+c}$ is a more accu...
\dfrac{22}{7}
math
162
Find the area of the region in the \(xy\)-plane satisfying \(x^{6} - x^{2} + y^{2} \leq 0\).
\frac{\pi}{2}
math
36
Bill’s age is one third larger than Tracy’s age. In $30$ years Bill’s age will be one eighth larger than Tracy’s age. How many years old is Bill?
24
math
40
Given a complex number $Z$ that satisfies $Z(i - 1) = 2i$ (where $i$ is the imaginary unit), determine the conjugate of $Z$.
1 + i
math
39
The distance between the two intersections of $x=y^4$ and $x+y^2=1$ is $\sqrt{u+v\sqrt5}$. Find the ordered pair, $(u,v)$.
(-2,2)
math
44
Find the domain of the following functions (the result should be expressed as a set or interval): (1) $$y= \frac { \sqrt {x-4}}{|x|-5}$$ (2) $y=\log_{a}(2-x)$ ($a>0$ and $a\neq 1$) (3) $$y= \sqrt {1-\left( \frac {1}{2}\right)^{x}}$$.
[0, +\infty)
math
99
A thousand points form the vertices of a convex polygon with 1000 sides. Inside this polygon, there are another 500 points placed such that no three of these 500 points are collinear. The polygon is triangulated in such a way that all of these 1500 points are vertices of the triangles, and none of the triangles have an...
1998
math
90
The original price of "Fun Math Stories" is 25 yuan, and the current price is 20 yuan. The current price is     % of the original price.
80\%
math
38
Compute $$\sum_{k=1}^{1000} k(\lceil \log_{\sqrt{2}}{k}\rceil- \lfloor\log_{\sqrt{2}}{k} \rfloor).$$
499477
math
53
In triangle $PQR$, the angle bisectors are $PL$, $QM$, and $RN$, which intersect at the incenter $I$. If $\angle PRQ = 24^\circ$, find the measure of $\angle PIM$, in degrees.
78^\circ
math
54
A pedestrian departed from point \( A \) to point \( B \). After walking 8 km, a second pedestrian left point \( A \) following the first pedestrian. When the second pedestrian had walked 15 km, the first pedestrian was halfway to point \( B \), and both pedestrians arrived at point \( B \) simultaneously. What is the ...
40
math
84
The sum of the roots of the equation $x^2+3ax+3a+1=0$ in terms of their tangents is equal to $\tan(\alpha+\beta)$.
\frac{\pi}{4}
math
40
The numbers $203$ and $298$ divided with the positive integer $x$ give both remainder $13$ . Which are the possible values of $x$ ?
19 \text{ or } 95
math
48
A straight line is tangent to the graphs of the functions $y=\ln x$ and $y=e^{x}$ at points $P(x_{1}, y_{1})$ and $Q(x_{2}, y_{2})$ respectively. The value of $(1-e^{y_1})(1+x_2)$ is ______.
2
math
70
If line $l$ passes through the point $( \sqrt {3}, -3)$ and has an inclination angle of $30°$, determine the equation of line $l$.
y+3= \frac {\sqrt{3}}{3}(x- \sqrt{3})
math
37
Let $S_n$ be the sum of the first $n$ terms of the sequence $\{a_n\}$, given that $a_1=3$, $a_{n+1}=2S_n+3$. $(1)$ Find the general formula for the sequence $\{a_n\}$. $(2)$ Let $b_n=(2n-1)a_n$, find the sum of the first $n$ terms of the sequence $\{b_n\}$, denoted as $T_n$.
T_n=3+(n-1)\cdot3^{n+1}
math
108
How many lattice points are exactly twice as close to $(0,0)$ as they are to $(15,0)$ ? (A lattice point is a point $(a,b)$ such that both $a$ and $b$ are integers.)
12
math
59
Given a regular tetrahedron with an edge length of $1$, calculate its volume.
\frac{\sqrt{2}}{12}
math
19
Given a geometric sequence $\{a_n\}$ with the first term $a_1$ and common ratio $q$, its general term $a_n$ is \_\_\_\_\_\_.
a_{1}q^{n-1}
math
40
Given the equation \( m\left(x^{2}+y^{2}+2 y+1\right) = (x - 2y + 3)^{2} \), determine the range of values for \( m \) such that the equation represents an ellipse.
(5,+\infty)
math
58
A rectangular yard has two flower beds in the form of congruent isosceles right triangles. The rest of the yard is a trapezoid. The parallel sides of the trapezoid measure $18$ and $30$ meters. Determine the fraction of the yard occupied by the flower beds.
\frac{1}{5}
math
65
Given proposition p: The real number $m$ satisfies $m^2 - 7ma + 12a^2 < 0$ ($a > 0$), and proposition q: The equation $\frac{x^2}{m-1} + \frac{y^2}{2-m} = 1$ represents an ellipse with foci on the y-axis. If $\neg p$ is a necessary but not sufficient condition for $\neg q$, find the range of values for the real number ...
\left[\frac{1}{3}, \frac{3}{8}\right]
math
108
The bottoms of two vertical poles are 20 feet apart on a flat ground. One pole is 8 feet tall and the other is 18 feet tall. Simultaneously, the ground between the poles is sloped, with the base of the taller pole being 2 feet higher than the base of the shorter pole due to the slope. Calculate the length in feet of a ...
\sqrt{544}
math
95
How many different rectangles with sides parallel to the grid can be formed by connecting four of the dots in a $5\times 5$ square array of dots? (Two rectangles are different if they do not share all four vertices.)
100
math
47
Given that $\frac{n}{p\_1+p\_2+...+p\_n}$ is the "harmonic mean" of $n$ positive numbers $p\_1$, $p\_2$, ..., $p\_n$, and the harmonic mean of the first $n$ terms of the sequence $\{a\_n\}$ is $\frac{1}{n}$, determine the value of $\frac{1}{a\_1a\_2} + \frac{1}{a\_2a\_3} + ... + \frac{1}{a\_10a\_11}$.
\frac{10}{21}
math
125
Tyrone had $97$ marbles and Eric had $11$ marbles. Tyrone then gave some of his marbles to Eric so that Tyrone ended with twice as many marbles as Eric. Calculate the number of marbles Tyrone gave to Eric.
25
math
57
Calculate the value of $-1+2-3+4-5+6+\ldots -2021+2022-2023$.
-1012
math
36
Given the circle O: $x^2+y^2=1$ and a fixed point A(2, 1), a point P outside circle O draws a tangent PQ to circle O, satisfying $|PQ|=|PA|$. If the circle with center P and radius r has a common point with circle O, calculate the minimum value of r.
\frac{3\sqrt{5}}{5} - 1
math
74
In the Cartesian coordinate system $xOy$, with $O$ as the pole and the positive half-axis of the $x$-axis as the polar axis, establish a polar coordinate system. Given that the parametric equations of line $l$ are $\begin{cases}x=-1+t \\ y=1+t\end{cases}$ (with $t$ as the parameter), and the general equation of curve $...
S_{\triangle PAB} = \frac{1}{2} \times 3\sqrt{2} \times 2\sqrt{2} = 6
math
204
In the Mathematical Competition of HMS (Hellenic Mathematical Society) take part boys and girls who are divided into two groups : *Juniors* and *seniors.*The number of the boys taking part of this year competition is 55% of the number of all participants. The ratio of the number of juniors ...
\frac{11}{9}
math
150
Given a geometric sequence $\{a_n\}$ satisfies $a_2a_6=64$ and $a_3a_4=32$, find the common ratio $q=\boxed{\text{answer}}$; and the sum $a_1^2+a_2^2+\ldots+a_n^2=\boxed{\text{answer}}$.
\frac{4^n-1}{3}
math
78
Given $2^{202} +202$ is divided by $2^{101}+2^{51}+1$, calculate the remainder.
201
math
36
If the monotonically decreasing interval of the function $f(x)=a(x^{3}-x)$ is $\left(- \frac{ \sqrt{3}}{3}, \frac{ \sqrt{3}}{3}\right)$, then the range of values for $a$ is $\_\_\_\_\_\_\_\_\_\_.$
a > 0
math
72
The solution interval for the equation $\log_{3}x + x = 3$ is $(2,3)$.
(2,3)
math
25
If \( A \) and \( B \) are relatively prime numbers, then the greatest common divisor of \( A^{3} + B^{3} \) and \( A^{2} + B^{2} \) is either 1 or 2.
1 \text{ or } 2
math
54
Let $\square B_1B_2B_3B_4$ be a square, and define $B_{n+4}$ to be the midpoint of the line segment $B_nB_{n+1}$ for all positive integers $n$. Find the measure of $\measuredangle B_{101}B_{102}B_{100}$. A) $45^\circ$ B) $60^\circ$ C) $90^\circ$ D) $120^\circ$ E) $135^\circ$
90^\circ
math
122
Ice-cream-o-rama has expanded its range of basic flavors to include mint, along with the traditional chocolate, vanilla, and strawberry. Using these four basic flavors, they now make "new" flavors by blending together five scoops of ice cream. Different proportions of the basic flavors create different new flavors. Ho...
56
math
80
Given the hyperbola $C: \frac{x^{2}}{a^{2}} - \frac{y^{2}}{b^{2}} = 1 (a > 0, b > 0)$ with an eccentricity of $\sqrt{5}$, and the distance from point $P(\sqrt{a^{2} + b^{2}}, 0)$ to its asymptotes is $8$, determine the length of the real axis of $C$.
8
math
98
Find the greatest integer $A$ for which in any permutation of the numbers $1, 2, \ldots , 100$ there exist ten consecutive numbers whose sum is at least $A$ .
505
math
49
Calculate $\frac{(1+i)^{2}}{(1-i)^{3}}$.
-\frac{1}{2}-\frac{1}{2}i
math
18
Given triangle $\text{ABC}$ with internal angles $\text{A}$, $\text{B}$, and $\text{C}$, and their respective opposite sides $a$, $b$, and $c$. Let $a=4$, $c=\sqrt{13}$, and $\sin\text{A}=4\sin\text{B}$. (1) Find the length of side $b$. (2) Find the measure of angle $\text{C}$.
\text{C}=60^\circ
math
102
In the first year of high school, Hua Hua found that for a finite set $A$, it is generally possible to find two non-empty sets $A_{1}$ and $A_{2}$, satisfying $A_{1}$ ⋂ $A_{2}$ = $\varnothing$, and $A_{1} \cup A_{2}$ = $A$. The set $\{A_{1}$, $A_{2}\}$ is called a "partition set" of $A$. If there are $n$ ($n \geq 2$, $...
2^{n-1} - 1
math
159
The time right now is exactly midnight. What time will it be in 2405 minutes?
4\!:\!05 \text{ p.m.}
math
21
John's bookshelf holds seven books with the following widths in centimeters: $7$, $\frac{3}{4}$, $1.25$, $3$, $8$, $2.5$, and $12$. What is the average book width, in centimeters? A) $\frac{241}{49}$ cm B) $5$ cm C) $4$ cm D) $3$ cm E) $3.5$ cm
\frac{241}{49}
math
102
A regular triangle \( \triangle ABC \) with side length 3 is divided into three equal parts on each side. Parallel lines to each side are drawn through these division points, creating a total of 10 intersection points within and on the edges of the triangle, known as grid points. Determine the minimum number \( n \) of...
5
math
103
Soda is now sold in packs of 8, 15, and 30 cans. Find the minimum number of packs needed to buy exactly 130 cans of soda.
6
math
39
Given $$\frac{\cos(\pi - 2\alpha)}{\sin(\alpha - \frac{\pi}{4})} = -\frac{\sqrt{2}}{2},$$ find the value of $\sin 2\alpha$.
-\frac{3}{4}
math
51
The number of integers between 208 and 2008 ending with 1 is:
180
math
21
Observe the following equations about converting repeating decimals to fractions: (Note: the numbers with dots on top) $0.\dot{3} = \frac{3}{9} = \frac{1}{3}$, $1.\dot{1}\dot{8} = \frac{18}{99} = \frac{2}{11}$, $0.\dot{3}\dot{5}\dot{2} = \frac{352}{999}$, $0.000\dot{5}\dot{9} = \frac{1}{1000} \times \frac{59}{99} = \fr...
\frac{7}{30}
math
178
In the diagram, triangles $ABC$ and $CBD$ are isosceles. Triangle $ABC$ has $\angle BAC = 2 \times \angle ABC$. The perimeter of $\triangle CBD$ is $21$, the perimeter of $\triangle ABC$ is $26$, and the length of $BD$ is $9$. What is the length of $AB$?
10
math
80
Let $\mathbf{p}$ be the projection of vector $\mathbf{v}$ onto vector $\mathbf{u},$ and let $\mathbf{q}$ be the projection of $\mathbf{p}$ onto $\mathbf{u}.$ If $\frac{\|\mathbf{p}\|}{\|\mathbf{v}\|} = \frac{3}{4},$ then find $\frac{\|\mathbf{q}\|}{\|\mathbf{u}\|}.$
\frac{9}{16}
math
106
The minimum value of the function $y=\sin x+ \sqrt{3}\cos x$ is to be found.
-2
math
25
Given that $|\overset{→}{a}| = 1$, $|\overset{→}{b}| = 2$, the angle between $\overset{→}{a}$ and $\overset{→}{b}$ is $120^{\circ}$, and $\overset{→}{a} + \overset{→}{b} + \overset{→}{c} = \overset{→}{0}$, find the angle between $\overset{→}{a}$ and $\overset{→}{c}$.
90^{\circ}
math
117
The point $O$ is the center of the circle circumscribed about $\triangle ABC$, with $\angle BOC = 150^{\circ}$ and $\angle AOB = 130^{\circ}$, as shown. What is the degree measure of $\angle ABC$?
40^\circ
math
62
For constants $a$ and $b$, let \[f(x) = \left\{ \begin{array}{cl} ax + b & \text{if } x < 1, \\ 7 - 2x & \text{if } x \ge 1. \end{array} \right.\] The function $f$ has the property that $f(f(x)) = x$ for all $x$. What is the value of $a + b$?
3
math
101
In the arithmetic sequence $\{a\_n\}$, $a\_1 = -60$ and $a\_17 = -12$. (1) Find the nth term, $a\_n$; (2) Find the sum of the absolute values of the first 30 terms in this sequence.
765
math
68
Find all values of the parameter $m$ such that the equations $x^2 = 2^{|x|} + |x| - y - m = 1 - y^2$ have only one root.
m = 0
math
50
A smooth sphere with a radius of 1 cm was dipped in blue paint and placed between two absolutely smooth concentric spheres with radii of 4 cm and 6 cm, respectively (the sphere was outside the smaller sphere but inside the larger one). When in contact with both spheres, the sphere leaves a blue trace. While moving, the...
38.25
math
128
Let $x,$ $y,$ and $z$ be angles such that \begin{align*} \sin x &= \cot y, \\ \sin y &= \cot z, \\ \sin z &= \cot x. \end{align*} Find the minimum possible value of $\cos x.$
\sqrt{\frac{3 - \sqrt{5}}{2}}
math
64
A spherical soap bubble lands on a horizontal wet surface and forms a hemisphere. The volume of the hemisphere is known to be $36\pi$ cm³. Find the radius of the original bubble.
3 \text{ cm}
math
41
Find the minimum value of \[(13 - x)(11 - x)(13 + x)(11 + x) + 1000.\]
424
math
36
Given an arithmetic sequence $\{a_n\}$ with the first term $a_1=1$ and a common difference $d>0$, and a geometric sequence $\{b_n\}$, satisfying $b_2=a_2$, $b_3=a_5$, $b_4=a_{14}$. (1) Find the general term of the sequences $\{a_n\}$ and $\{b_n\}$. (2) Let the sequence $\{c_n\}$ satisfy $c_n=2a_n-18$, find the mini...
-40
math
157
Given a finite sequence $a_1, a_2, a_3, \ldots, a_n$ (where $n$ is a positive integer) that satisfies the conditions $a_1 = a_n$, $a_2 = a_n-1$, $\ldots$, $a_n = a_1$, i.e., $a_k = a_{n-k+1}$ (for $k=1, 2, \ldots, n$), we call it a "symmetric sequence". Let $\{b_n\}$ be a symmetric sequence with 7 terms, where $b_1, b_...
2, 5, 8, 11, 8, 5, 2
math
182
When $x \in [1,2]$, the inequality $2^{x}-\log_{\frac{1}{2}}x+m\leqslant 0$ always holds, then the range of the real number $m$ is \_\_\_\_\_\_.
(-\infty,-5]
math
59
Given the power function $f(x)=({{m^2}-m-1}){x^{\frac{1}{m}}}$ is monotonically increasing on $(0,+\infty)$, the value of the real number $m$ is ____.
2
math
55
Given that the perimeter of a sector of a circle is $16$, find the radius and central angle of the sector when its area is at its maximum. Also, find the maximum area.
16
math
39
\(8.469 \sin^{4} x + 2 \cos^{3} x + 2 \sin^{2} x - \cos x + 1 = 0\).
x = \pi(2k + 1)
math
42
Find the number of odd digits in the base-4 representation of $317_{10}$.
4
math
22
A larger deck of cards contains 104 cards divided into 4 suits, each of which has 26 cards. Two of the suits ($\heartsuit$ and $\diamondsuit$) are red, and the other two ($\spadesuit$ and $\clubsuit$) are black. The cards in this deck are shuffled randomly. What is the probability that the first three cards drawn from ...
\frac{425}{3502}
math
90
A point $P(x, y)$ is randomly selected from the set $M={(x,y)∣(|x|−1)^2+(|y|−1)^2 < 4$, $x$, $y∈Z}$. If the probability that $xy≥k (k > 0)$ is $\frac{6}{25}$, what is the maximum value of $k$?
2
math
83
In $\triangle ABC$, let $A$, $B$, and $C$ be the three interior angles, and $a$, $b$, and $c$ be the sides opposite these angles, respectively. Given that: \[2 \sqrt{2}\left(\sin ^{2} A-\sin ^{2} C\right) = (a-b) \sin B,\] and the circumradius of $\triangle ABC$ is $\sqrt{2}$. (1) Find angle $C$. (2) Find the maximum...
\frac{3\sqrt{3}}{2}
math
125
Let $x$ be chosen at random from the interval $(0,1)$. What is the probability that $\lfloor\log_{10}5x\rfloor - \lfloor\log_{10}x\rfloor = 0$? Here $\lfloor x\rfloor$ denotes the greatest integer that is less than or equal to $x$. A) $\frac{1}{7}$ B) $\frac{1}{9}$ C) $\frac{1}{10}$ D) $\frac{1}{8}$ E) $\frac{2}{9}$
\frac{1}{9}
math
130