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742k
## Problem Statement Calculate the limit of the function: $$ \lim _{x \rightarrow-2} \frac{x^{3}+5 x^{2}+8 x+4}{x^{3}+3 x^{2}-4} $$
## Solution $$ \begin{aligned} & \lim _{x \rightarrow-2} \frac{x^{3}+5 x^{2}+8 x+4}{x^{3}+3 x^{2}-4}=\left\{\frac{0}{0}\right\}=\lim _{x \rightarrow-2} \frac{(x+2)\left(x^{2}+3 x+2\right)}{(x+2)\left(x^{2}+x-2\right)}= \\ & =\lim _{x \rightarrow-2} \frac{x^{2}+3 x+2}{x^{2}+x-2}=\left\{\frac{0}{0}\right\}=\lim _{x \rig...
\frac{1}{3}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,842
## Problem Statement Calculate the limit of the function: $\lim _{x \rightarrow 3} \frac{\sqrt[3]{9 x}-3}{\sqrt{3+x}-\sqrt{2 x}}$
## Solution $$ \begin{aligned} & \lim _{x \rightarrow 5} \frac{\sqrt[3]{9 x}-3}{\sqrt{3+x}-\sqrt{2 x}}=\lim _{x \rightarrow 3} \frac{(\sqrt[3]{9 x}-3)\left(\sqrt[3]{(9 x)^{2}}+\sqrt[3]{9 x} \cdot 3+9\right)}{(\sqrt{3+x}-\sqrt{2 x})\left(\sqrt[3]{(9 x)^{2}}+\sqrt[3]{9 x} \cdot 3+9\right)}= \\ & =\lim _{x \rightarrow 3}...
-\frac{2\sqrt{6}}{3}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,843
## Problem Statement Calculate the limit of the function: $$ \lim _{x \rightarrow 1} \frac{3^{5 x-3}-3^{2 x^{2}}}{\tan \pi x} $$
## Solution $\lim _{x \rightarrow 1} \frac{3^{5 x-3}-3^{2 x^{2}}}{\tan \pi x}=\lim _{x \rightarrow 1} \frac{3^{2 x^{2}}\left(3^{5 x-3-2 x^{2}}-1\right)}{\tan \pi x}=$[^0]$x=y+1 \Rightarrow y=x-1$ $x \rightarrow 1 \Rightarrow y \rightarrow 0$ We get: $$ \begin{aligned} & =\lim _{y \rightarrow 0} \frac{3^{2(y+1)^{2}}...
\frac{9\ln3}{\pi}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,845
## Problem Statement Calculate the limit of the function: $\lim _{x \rightarrow 1} \frac{\sqrt[3]{1+\ln ^{2} x}-1}{1+\cos \pi x}$
## Solution Substitution: $x=y+1 \Rightarrow y=x-1$ $x \rightarrow 1 \Rightarrow y \rightarrow 0$ We get: $$ \begin{aligned} & \lim _{x \rightarrow 1} \frac{\sqrt[3]{1+\ln ^{2} x}-1}{1+\cos \pi x}=\lim _{y \rightarrow 0} \frac{\sqrt[3]{1+\ln ^{2}(y+1)}-1}{1+\cos \pi(y+1)}= \\ & =\lim _{y \rightarrow 0} \frac{\sqrt[...
\frac{2}{3\pi^{2}}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,846
## Problem Statement Calculate the limit of the function: $\lim _{x \rightarrow 0} \frac{10^{2 x}-7^{-x}}{2 \tan x-\arctan x}$
## Solution $\lim _{x \rightarrow 0} \frac{10^{2 x}-7^{-x}}{2 \tan x-\arctan x}=\lim _{x \rightarrow 0} \frac{\left(100^{x}-1\right)-\left(7^{-x}-1\right)}{2 \tan x-\arctan x}=$ $=\lim _{x \rightarrow 0} \frac{\left(\left(e^{\ln 100}\right)^{x}-1\right)-\left(\left(e^{\ln 7}\right)^{-x}-1\right)}{2 \tan x-\arctan x}=...
\ln700
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,847
## Problem Statement Calculate the limit of the function: $\lim _{h \rightarrow 0} \frac{\ln (x+h)+\ln (x-h)-2 \ln x}{h^{2}}, x>0$
## Solution $\lim _{h \rightarrow 0} \frac{\ln (x+h)+\ln (x-h)-2 \ln x}{h^{2}}=\lim _{h \rightarrow 0} \frac{\ln ((x+h)(x-h))-\ln x^{2}}{h^{2}}=$ $=\lim _{h \rightarrow 0} \frac{\ln \frac{x^{2}-h^{2}}{x^{2}}}{h^{2}}=\lim _{h \rightarrow 0} \frac{\ln \left(1-\frac{h^{2}}{x^{2}}\right)}{h^{2}}=$ Using the substitution...
-\frac{1}{x^{2}}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,848
## Problem Statement Calculate the limit of the function: $\lim _{x \rightarrow 0}\left(2-e^{\sin x}\right)^{\operatorname{ctg} \pi x}$
## Solution $\lim _{x \rightarrow 0}\left(2-e^{\sin x}\right)^{\operatorname{ctg} \pi x}=\lim _{x \rightarrow 0}\left(e^{\ln \left(2-e^{\sin x}\right)}\right)^{\operatorname{ctg} \pi x}=$ $=\lim _{x \rightarrow 0} e^{\operatorname{ctg} \pi x \cdot \ln \left(2-e^{\sin x}\right)}=$ $=\exp \left\{\lim _{x \rightarrow 0...
e^{-\frac{1}{\pi}}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,849
## Problem Statement Calculate the limit of the function: $\lim _{x \rightarrow 0}\left(\frac{x^{3}+8}{3 x^{2}+10}\right)^{x+2}$
## Solution $\lim _{x \rightarrow 0}\left(\frac{x^{3}+8}{3 x^{2}+10}\right)^{x+2}=\left(\frac{0^{3}+8}{3 \cdot 0^{2}+10}\right)^{0+2}=$ $=\left(\frac{8}{10}\right)^{2}=0.8^{2}=0.64$ Problem Kuznetsov Limits 18-15
0.64
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,850
## Condition of the problem Calculate the limit of the function: $$ \lim _{x \rightarrow 3}\left(\frac{9-2 x}{3}\right)^{\tan\left(\frac{\pi x}{6}\right)} $$
## Solution $$ \begin{aligned} & \lim _{x \rightarrow 3}\left(\frac{9-2 x}{3}\right)^{\operatorname{tg}\left(\frac{\pi x}{6}\right)}=\lim _{x \rightarrow 3}\left(3-\frac{2 x}{3}\right)^{\operatorname{tg}\left(\frac{\pi x}{6}\right)}= \\ & =\lim _{x \rightarrow 3}\left(e^{\ln \left(3-\frac{2 x}{3}\right)}\right)^{\oper...
e^{\frac{4}{\pi}}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,851
## Problem Statement Calculate the limit of the function: $\lim _{x \rightarrow a}\left(\frac{\sin x-\sin a}{x-a}\right)^{\frac{x^{2}}{a^{2}}}$
## Solution $\lim _{x \rightarrow a}\left(\frac{\sin x-\sin a}{x-a}\right)^{\frac{x^{2}}{a^{2}}}=\left(\lim _{x \rightarrow a} \frac{\sin x-\sin a}{x-a}\right)^{\lim _{x \rightarrow a} \frac{x^{2}}{a^{2}}}=$ $=\left(\lim _{x \rightarrow a} \frac{2 \sin \frac{x-a}{2} \cos \frac{x+a}{2}}{x-a}\right)^{\frac{a^{2}}{a^{2}...
\cos
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,852
## Problem Statement Write the decomposition of vector $x$ in terms of vectors $p, q, r$: $x=\{11 ;-1 ; 4\}$ $p=\{1 ;-1 ; 2\}$ $q=\{3 ; 2 ; 0\}$ $r=\{-1 ; 1 ; 1\}$
## Solution The desired decomposition of vector $x$ is: $x=\alpha \cdot p+\beta \cdot q+\gamma \cdot r$ Or in the form of a system: $$ \left\{\begin{array}{l} \alpha \cdot p_{1}+\beta \cdot q_{1}+\gamma \cdot r_{1}=x_{1} \\ \alpha \cdot p_{2}+\beta \cdot q_{2}+\gamma \cdot r_{2}=x_{2} \\ \alpha \cdot p_{3}+\beta \c...
3p+2q-2r
Algebra
math-word-problem
Yes
Yes
olympiads
false
46,854
## Problem Statement Are the vectors $c_{1 \text { and }} c_{2}$, constructed from vectors $a \text{ and } b$, collinear? $a=\{2 ;-1 ; 6\}$ $b=\{-1 ; 3 ; 8\}$ $c_{1}=5 a-2 b$ $c_{2}=2 a-5 b$
## Solution Vectors are collinear if there exists a number $\gamma$ such that $c_{1}=\gamma \cdot c_{2}$. That is, vectors are collinear if their coordinates are proportional. We find: $$ \begin{aligned} & c_{1}=5 a-2 b=\{5 \cdot 2-2 \cdot(-1) ; 5 \cdot(-1)-2 \cdot 3 ; 5 \cdot 6-2 \cdot 8\}=\{12 ;-11 ; 14\} \\ & c_{...
proof
Algebra
math-word-problem
Yes
Yes
olympiads
false
46,855
## Problem Statement Find the cosine of the angle between vectors $\overrightarrow{A B}$ and $\overrightarrow{A C}$. $A(3 ; 3 ;-1), B(5 ; 1 ;-2), C(4 ; 1 ;-3)$
## Solution Let's find $\overrightarrow{A B}$ and $\overrightarrow{A C}$: $\overrightarrow{A B}=(5-3 ; 1-3 ;-2-(-1))=(2 ;-2 ;-1)$ $\overrightarrow{A C}=(4-3 ; 1-3 ;-3-(-1))=(1 ;-2 ;-2)$ We find the cosine of the angle $\phi$ between the vectors $\overrightarrow{A B}$ and $\overrightarrow{A C}$: $\cos (\overrightar...
\frac{8}{9}
Algebra
math-word-problem
Yes
Yes
olympiads
false
46,856
## Task Condition Calculate the area of the parallelogram constructed on vectors $a_{\text {and }} b$. $$ \begin{aligned} & a=5 p-q \\ & b=p+q \\ & |p|=5 \\ & |q|=3 \\ & (\widehat{p, q})=\frac{5 \pi}{6} \end{aligned} $$
## Solution The area of the parallelogram constructed on vectors $a$ and $b$ is numerically equal to the modulus of their vector product: $S=|a \times b|$ We compute $a \times b$ using the properties of the vector product: $a \times b=(5 p-q) \times(p+q)=5 \cdot p \times p+5 \cdot p \times q-q \times p-q \times q=$...
45
Algebra
math-word-problem
Yes
Yes
olympiads
false
46,857
## Task Condition Are the vectors $a, b$ and $c$ coplanar? $a=\{1 ;-1 ; 4\}$ $b=\{1 ; 0 ; 3\}$ $c=\{1 ;-3 ; 8\}$
## Solution For three vectors to be coplanar (lie in the same plane or parallel planes), it is necessary and sufficient that their scalar triple product $(a, b, c)$ be equal to zero. $(a, b, c)=\left|\begin{array}{ccc}1 & -1 & 4 \\ 1 & 0 & 3 \\ 1 & -3 & 8\end{array}\right|=$ $=1 \cdot\left|\begin{array}{cc}0 & 3 \\ -...
2
Algebra
math-word-problem
Yes
Yes
olympiads
false
46,858
## Task Condition Calculate the volume of the tetrahedron with vertices at points $A_{1}, A_{2}, A_{3}, A_{4_{\text {and }}}$ its height dropped from vertex $A_{4 \text { to the face }} A_{1} A_{2} A_{3}$. $A_{1}(0 ;-3 ; 1)$ $A_{2}(-4 ; 1 ; 2)$ $A_{3}(2 ;-1 ; 5)$ $A_{4}(3 ; 1 ;-4)$
## Solution From vertex $A_{1 \text {, we draw vectors: }}$ $\overrightarrow{A_{1} A_{2}}=\{-4-0 ; 1-(-3) ; 2-1\}=\{-4 ; 4 ; 1\}$ $\overrightarrow{A_{1} A_{3}}=\{2-0 ;-1-(-3) ; 5-1\}=\{2 ; 2 ; 4\}$ $\overrightarrow{A_{1} A_{4}}=\{3-0 ; 1-(-3) ;-4-1\}=\{3 ; 4 ;-5\}$ According to the geometric meaning of the scalar ...
32\frac{1}{3}
Geometry
math-word-problem
Yes
Yes
olympiads
false
46,859
## Problem Statement Find the distance from point $M_{0}$ to the plane passing through three points $M_{1}, M_{2}, M_{3}$. $M_{1}(1 ; 2 ; 0)$ $M_{2}(3 ; 0 ;-3)$ $M_{3}(5 ; 2 ; 6)$ $M_{0}(-13 ;-8 ; 16)$
## Solution Find the equation of the plane passing through three points $M_{1}, M_{2}, M_{3}$: $$ \left|\begin{array}{ccc} x-1 & y-2 & z-0 \\ 3-1 & 0-2 & -3-0 \\ 5-1 & 2-2 & 6-0 \end{array}\right|=0 $$ Perform transformations: $$ \begin{aligned} & \left|\begin{array}{ccc} x-1 & y-2 & z \\ 2 & -2 & -3 \\ 4 & 0 & 6 \...
\frac{134}{7}
Geometry
math-word-problem
Yes
Yes
olympiads
false
46,860
## Problem Statement Write the equation of the plane passing through point $A$ and perpendicular to vector $\overrightarrow{B C}$. $A(-3, -1, 7)$ $B(0, 2, -6)$ $C(2, 3, -5)$
## Solution Let's find the vector $\overrightarrow{BC}:$ $\overrightarrow{BC}=\{2-0 ; 3-2 ;-5-(-6)\}=\{2 ; 1 ; 1\}$ Since the vector $\overrightarrow{BC}$ is perpendicular to the desired plane, it can be taken as the normal vector. Therefore, the equation of the plane will be: $2 \cdot(x-(-3))+(y-(-1))+(z-7)=0$ $2 ...
2x+y+0
Geometry
math-word-problem
Yes
Yes
olympiads
false
46,861
## Task Condition Find the angle between the planes: $2 y+z-9=0$ $x-y+2 z-1=0$
## Solution The dihedral angle between planes is equal to the angle between their normal vectors. The normal vectors of the given planes are: $\overrightarrow{n_{1}}=\{0 ; 2 ; 1\}$ $\overrightarrow{n_{2}}=\{1 ;-1 ; 2\}$ The angle $\phi$ between the planes is determined by the formula: $\cos \phi=\frac{\left(\overr...
\frac{\pi}{2}
Geometry
math-word-problem
Yes
Yes
olympiads
false
46,862
## Problem Statement Find the coordinates of point $A$, which is equidistant from points $B$ and $C$. $A(x ; 0 ; 0)$ $B(4 ; 5 ;-2)$ $C(2 ; 3 ; 4)$
## Solution Let's find the distances $A B$ and $A C$: $$ \begin{aligned} & A B=\sqrt{(4-x)^{2}+(5-0)^{2}+(-2-0)^{2}}=\sqrt{16-8 x+x^{2}+25+4}=\sqrt{x^{2}-8 x+45} \\ & A C=\sqrt{(2-x)^{2}+(3-0)^{2}+(4-0)^{2}}=\sqrt{4-4 x+x^{2}+9+16}=\sqrt{x^{2}-4 x+29} \end{aligned} $$ Since according to the problem's condition $A B=...
A(4;0;0)
Algebra
math-word-problem
Yes
Yes
olympiads
false
46,863
## Problem Statement Let $k$ be the coefficient of similarity transformation with the center at the origin. Is it true that point $A$ belongs to the image of plane $a$? $A(-3; -2; 4)$ $a: 2x - 3y + z - 5 = 0$ $k = -\frac{4}{5}$
## Solution When transforming similarity with the center at the origin of the plane $a: A x+B y+C z+D=0_{\text{and coefficient }} k$ transitions to the plane $a^{\prime}: A x+B y+C z+k \cdot D=0$. We find the image of the plane $a$: $a^{\prime}: 2 x-3 y+z+4=0$ Substitute the coordinates of point $A$ into the equat...
8\neq0
Geometry
math-word-problem
Yes
Yes
olympiads
false
46,864
## Task Condition Write the canonical equations of the line. $x-3 y+z+2=0$ $x+3 y+2 z+14=0$
## Solution Canonical equations of a line: $\frac{x-x_{0}}{m}=\frac{y-y_{0}}{n}=\frac{z-z_{0}}{p}$ where $\left(x_{0} ; y_{0} ; z_{0}\right)_{\text {- are coordinates of some point on the line, and }} \vec{s}=\{m ; n ; p\}$ - its direction vector. Since the line belongs to both planes simultaneously, its direction ...
\frac{x+8}{-9}=\frac{y+2}{-1}=\frac{z}{6}
Algebra
math-word-problem
Yes
Yes
olympiads
false
46,865
## Problem Statement Find the point of intersection of the line and the plane. $\frac{x-1}{6}=\frac{y-3}{1}=\frac{z+5}{3}$ $3 x-2 y+5 z-3=0$
## Solution Let's write the parametric equations of the line. $$ \begin{aligned} & \frac{x-1}{6}=\frac{y-3}{1}=\frac{z+5}{3}=t \Rightarrow \\ & \left\{\begin{array}{l} x=1+6 t \\ y=3+t \\ z=-5+3 t \end{array}\right. \end{aligned} $$ Substitute into the equation of the plane: $3(1+6 t)-2(3+t)+5(-5+3 t)-3=0$ $3+18 t...
(7;4;-2)
Algebra
math-word-problem
Yes
Yes
olympiads
false
46,866
## problem statement Find the point $M^{\prime}$ symmetric to the point $M$ with respect to the plane. $M(3 ;-3 ;-1)$ $2 x-4 y-4 z-13=0$
## Solution Let's find the equation of the line that is perpendicular to the given plane and passes through point $M$. Since the line is perpendicular to the given plane, we can take the normal vector of the plane as its direction vector: $$ \vec{s}=\vec{n}=\{2 ;-4 ;-4\} $$ Then the equation of the desired line is: ...
M^{\}(2;-1;1)
Geometry
math-word-problem
Yes
Yes
olympiads
false
46,867
## Problem Statement Calculate the definite integral: $$ \int_{e+1}^{e^{2}+1} \frac{1+\ln (x-1)}{x-1} d x $$
## Solution $$ \begin{aligned} & \int_{e+1}^{e^{2}+1} \frac{1+\ln (x-1)}{x-1} d x=\int_{e+1}^{e^{2}+1} \frac{1}{x-1} d x+\int_{e+1}^{e^{2}+1} \frac{\ln (x-1)}{x-1} d x= \\ & =\left.\ln |x-1|\right|_{e+1} ^{e^{2}+1}+\int_{e+1}^{e^{2}+1} \ln (x-1) d(\ln (x-1))= \\ & =\ln \left|e^{2}+1-1\right|-\ln |e+1-1|+\left.\frac{1}...
2\frac{1}{2}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,868
## Problem Statement Calculate the definite integral: $$ \int_{0}^{1} \frac{\left(x^{2}+1\right) d x}{\left(x^{3}+3 x+1\right)^{2}} $$
## Solution $$ \begin{aligned} & \int_{0}^{1} \frac{\left(x^{2}+1\right) d x}{\left(x^{3}+3 x+1\right)^{2}}=\int_{0}^{1} \frac{\frac{1}{3} \cdot\left(3 x^{2}+3\right) d x}{\left(x^{3}+3 x+1\right)^{2}}=\int_{0}^{1} \frac{\frac{1}{3} \cdot d\left(x^{3}+3 x+1\right)}{\left(x^{3}+3 x+1\right)^{2}}= \\ & =\left.\frac{1}{3...
\frac{4}{15}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,869
## Problem Statement Calculate the definite integral: $$ \int_{0}^{1} \frac{4 \operatorname{arctg} x - x}{1 + x^{2}} d x $$
## Solution $$ \begin{aligned} & \int_{0}^{1} \frac{4 \operatorname{arctg} x - x}{1 + x^{2}} d x = 4 \cdot \int_{0}^{1} \frac{\operatorname{arctg} x}{1 + x^{2}} d x - \int_{0}^{1} \frac{x}{1 + x^{2}} d x = \\ & = 4 \cdot \int_{0}^{1} \operatorname{arctg} x \cdot d(\operatorname{arctg} x) - \frac{1}{2} \cdot \int_{0}^{...
\frac{\pi^{2}-4\cdot\ln2}{8}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,870
## Problem Statement Calculate the definite integral: $$ \int_{0}^{2} \frac{x^{3}}{x^{2}+4} d x $$
## Solution $$ \begin{aligned} & \int_{0}^{2} \frac{x^{3}}{x^{2}+4} d x=\frac{1}{2} \cdot \int_{0}^{2} \frac{x^{2}}{x^{2}+4} d\left(x^{2}\right)=\frac{1}{2} \cdot \int_{0}^{2} \frac{x^{2}+4-4}{x^{2}+4} d\left(x^{2}\right)= \\ & =\frac{1}{2} \cdot \int_{0}^{2} d\left(x^{2}\right)-\frac{1}{2} \cdot \int_{0}^{2} \frac{4}...
2-2\ln2
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,871
## Problem Statement Calculate the definite integral: $$ \int_{\pi}^{2 \pi} \frac{x+\cos x}{x^{2}+2 \sin x} d x $$
## Solution $$ \begin{aligned} & \int_{\pi}^{2 \pi} \frac{x+\cos x}{x^{2}+2 \sin x} d x=\int_{\pi}^{2 \pi} \frac{\frac{1}{2}(2 x+2 \cos x)}{x^{2}+2 \sin x} d x=\frac{1}{2} \cdot \int_{\pi}^{2 \pi} \frac{d\left(x^{2}+2 \sin x\right)}{x^{2}+2 \sin x}= \\ & =\left.\frac{1}{2} \cdot \ln \left|x^{2}+2 \sin x\right|\right|_...
\ln2
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,872
## Problem Statement Calculate the definite integral: $$ \int_{0}^{\frac{\pi}{4}} \frac{2 \cos x + 3 \sin x}{(2 \sin x - 3 \cos x)^{3}} d x $$
## Solution $$ \begin{aligned} & \int_{0}^{\frac{\pi}{4}} \frac{2 \cos x+3 \sin x}{(2 \sin x-3 \cos x)^{3}} d x=\int_{0}^{\frac{\pi}{4}} \frac{d(2 \sin x-3 \cos x)}{(2 \sin x-3 \cos x)^{3}}=-\left.\frac{1}{2 \cdot(2 \sin x-3 \cos x)^{2}}\right|_{0} ^{\frac{\pi}{4}}= \\ & =-\frac{1}{2 \cdot\left(2 \sin \frac{\pi}{4}-3 ...
-\frac{17}{18}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,873
## Problem Statement Calculate the definite integral: $$ \int_{0}^{\frac{1}{2}} \frac{8 x-\operatorname{arctg} 2 x}{1+4 x^{2}} d x $$
## Solution $$ \begin{aligned} & \int_{0}^{\frac{1}{2}} \frac{8 x-\operatorname{arctg} 2 x}{1+4 x^{2}} d x=\int_{0}^{\frac{1}{2}} \frac{8 x}{1+4 x^{2}} d x-\int_{0}^{\frac{1}{2}} \frac{\operatorname{arctg} 2 x}{1+4 x^{2}} d x= \\ & =\int_{0}^{\frac{1}{2}} \frac{d\left(1+4 x^{2}\right)}{1+4 x^{2}}-\frac{1}{2} \cdot \in...
\ln2-\frac{\pi^2}{64}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,874
## Problem Statement Calculate the definite integral: $$ \int_{1}^{4} \frac{\frac{1}{2 \sqrt{x}}+1}{(\sqrt{x}+x)^{2}} d x $$
## Solution $$ \begin{aligned} & \int_{1}^{4} \frac{\frac{1}{2 \sqrt{x}}+1}{(\sqrt{x}+x)^{2}} d x=\int_{1}^{4} \frac{d(\sqrt{x}+x)}{(\sqrt{x}+x)^{2}}=-\left.\frac{1}{\sqrt{x}+x}\right|_{1} ^{4}= \\ & =-\frac{1}{\sqrt{4}+4}+\frac{1}{\sqrt{1}+1}=-\frac{1}{6}+\frac{1}{2}=\frac{2}{6}=\frac{1}{3} \end{aligned} $$ Source —...
\frac{1}{3}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,875
## Problem Statement Calculate the definite integral: $$ \int_{0}^{1} \frac{x}{x^{4}+1} d x $$
## Solution $$ \begin{aligned} & \int_{0}^{1} \frac{x}{x^{4}+1} d x=\frac{1}{2} \cdot \int_{0}^{1} \frac{d\left(x^{2}\right)}{x^{4}+1}=\frac{1}{2} \cdot \int_{0}^{1} \frac{d\left(x^{2}\right)}{x^{4}+1}=\left.\frac{1}{2} \cdot \operatorname{arctg} x^{2}\right|_{0} ^{1}= \\ & =\frac{1}{2} \cdot \operatorname{arctg} 1^{2...
\frac{\pi}{8}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,876
## Problem Statement Calculate the definite integral: $$ \int_{\sqrt{3}}^{\sqrt{8}} \frac{x+\frac{1}{x}}{\sqrt{x^{2}+1}} d x $$
## Solution $$ \begin{aligned} & \int_{\sqrt{3}}^{\sqrt{8}} \frac{x+\frac{1}{x}}{\sqrt{x^{2}+1}} d x=\int_{\sqrt{3}}^{\sqrt{8}} \frac{x}{\sqrt{x^{2}+1}} d x+\int_{\sqrt{3}}^{\sqrt{8}} \frac{1}{x \sqrt{x^{2}+1}} d x= \\ & =\frac{1}{2} \cdot \int_{\sqrt{3}}^{\sqrt{8}} \frac{d\left(x^{2}+1\right)}{\sqrt{x^{2}+1}}+\int_{\...
1+\ln\sqrt{\frac{3}{2}}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,877
## Problem Statement Calculate the definite integral: $$ \int_{\sqrt{3}}^{\sqrt{8}} \frac{x-\frac{1}{x}}{\sqrt{x^{2}+1}} d x $$
## Solution $$ \begin{aligned} & \int_{\sqrt{3}}^{\sqrt{8}} \frac{x-\frac{1}{x}}{\sqrt{x^{2}+1}} d x=\int_{\sqrt{3}}^{\sqrt{8}} \frac{x}{\sqrt{x^{2}+1}} d x-\int \frac{1}{x \sqrt{x^{2}+1}} d x= \\ & =\frac{1}{2} \cdot \int_{\sqrt{3}}^{\sqrt{8}} \frac{d\left(x^{2}+1\right)}{\sqrt{x^{2}+1}}-\int_{\sqrt{3}}^{\sqrt{8}} \f...
1+\ln\sqrt{\frac{2}{3}}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,878
## Problem Statement Calculate the definite integral: $$ \int_{0}^{\sqrt{3}} \frac{\operatorname{arctg} x + x}{1 + x^{2}} d x $$
## Solution $$ \begin{aligned} & \int_{0}^{\sqrt{3}} \frac{\operatorname{arctg} x + x}{1 + x^{2}} d x = \int_{0}^{\sqrt{3}} \frac{\operatorname{arctg} x}{1 + x^{2}} d x + \int_{0}^{\sqrt{3}} \frac{x}{1 + x^{2}} d x = \\ & = \frac{1}{2} \int_{0}^{\sqrt{3}} \operatorname{arctg} x d(\operatorname{arctg} x) + \frac{1}{2} ...
\frac{\pi^{2}}{18}+\ln2
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,879
## Problem Statement Calculate the definite integral: $$ \int_{0}^{\sqrt{3}} \frac{x-(\operatorname{arctg} x)^{4}}{1+x^{2}} d x $$
## Solution $$ \begin{aligned} & \int_{0}^{\sqrt{3}} \frac{x-(\operatorname{arctg} x)^{4}}{1+x^{2}} d x=\int_{0}^{\sqrt{3}} \frac{x d x}{1+x^{2}}-\int_{0}^{\sqrt{3}} \frac{(\operatorname{arctg} x)^{4}}{1+x^{2}}= \\ & =\frac{1}{2} \int_{0}^{\sqrt{3}} \frac{d\left(1+x^{2}\right)}{1+x^{2}}-\int_{0}^{\sqrt{3}}(\operatorna...
\ln2-\frac{\pi^5}{5\cdot3^5}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,880
## Problem Statement Calculate the definite integral: $$ \int_{0}^{1} \frac{x^{3}}{x^{2}+1} d x $$
## Solution $$ \begin{aligned} & \int_{0}^{1} \frac{x^{3}}{x^{2}+1} d x=\int_{0}^{1} \frac{x\left(x^{2}+1\right)-x}{x^{2}+1} d x=\int_{0}^{1} x d x-\int \frac{x}{x^{2}+1}= \\ & =\left.\frac{1}{2} x^{2}\right|_{0} ^{1}-\frac{1}{2} \int_{0}^{1} \frac{d\left(x^{2}+1\right)}{x^{2}+1}=\frac{1}{2} \cdot 1^{2}-\frac{1}{2} \c...
\frac{1-\ln2}{2}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,881
## Problem Statement Calculate the definite integral: $$ \int_{0}^{\sin 1} \frac{(\arcsin x)^{2}+1}{\sqrt{1-x^{2}}} d x $$
## Solution $$ \begin{aligned} & \int_{0}^{\sin 1} \frac{(\arcsin x)^{2}+1}{\sqrt{1-x^{2}}} d x=\int_{0}^{\sin 1} \frac{\arcsin ^{2} x}{\sqrt{1-x^{2}}} d x+\int_{0}^{\sin 1} \frac{d x}{\sqrt{1-x^{2}}}= \\ & =\int_{0}^{\sin 1}(\arcsin x)^{2} d(\arcsin x)+\left.\arcsin x\right|_{0} ^{\sin 1}= \\ & =\left.\frac{1}{3} \cd...
\frac{4}{3}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,882
## Problem Statement Calculate the definite integral: $$ \int_{1}^{3} \frac{1-\sqrt{x}}{\sqrt{x} \cdot(x+1)} d x $$
## Solution $$ \begin{aligned} & \int_{1}^{3} \frac{1-\sqrt{x}}{\sqrt{x} \cdot(x+1)} d x=\int_{1}^{3} \frac{1}{\sqrt{x} \cdot(x+1)} d x-\int_{1}^{3} \frac{1}{x+1} d x= \\ & =2 \cdot \int_{1}^{3} \frac{1}{x+1} d(\sqrt{x})-\ln |x+1|_{1}^{3}=\left.2 \operatorname{arctg} \sqrt{x}\right|_{1} ^{3}-\ln |3+1|+\ln |1+1|= \\ & ...
\frac{\pi}{6}-\ln2
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,883
## Problem Statement Calculate the definite integral: $$ \int_{\sqrt{3}}^{\sqrt{8}} \frac{d x}{x \sqrt{x^{2}+1}} $$
## Solution $$ \begin{aligned} & \int_{\sqrt{3}}^{\sqrt{8}} \frac{1}{x \sqrt{x^{2}+1}} d x=\int_{\sqrt{3}}^{\sqrt{8}} \frac{1}{x^{2} \cdot \frac{1}{x} \sqrt{x^{2}+1}} d x=\int_{\sqrt{3}}^{\sqrt{8}} \frac{1}{x^{2} \sqrt{1+\frac{1}{x^{2}}}} d x= \\ & =-\int_{\sqrt{3}}^{\sqrt{3}} \frac{1}{\sqrt{1+\frac{1}{x^{2}}}} d\left...
\ln\sqrt{\frac{3}{2}}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,884
## Problem Statement Calculate the definite integral: $$ \int_{1}^{e} \frac{1+\ln x}{x} d x $$
## Solution $$ \begin{aligned} & \int_{1}^{e} \frac{1+\ln x}{x} d x=\int_{1}^{e}(1+\ln x) d(\ln x)=\left.\left(\ln x+\frac{1}{2} \ln ^{2} x\right)\right|_{1} ^{e}= \\ & =\left(\ln e+\frac{1}{2} \ln ^{2} e\right)-\left(\ln 1+\frac{1}{2} \ln ^{2} 1\right)=\left(1+\frac{1}{2} \cdot 1^{2}\right)-\left(0+\frac{1}{2} \cdot ...
\frac{3}{2}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,885
## Problem Statement Calculate the definite integral: $$ \int_{\sqrt{2}}^{2} \frac{d x}{x \sqrt{x^{2}-1}} $$
## Solution $$ \begin{aligned} & \int_{\sqrt{2}}^{2} \frac{d x}{x \sqrt{x^{2}-1}}=\int_{\sqrt{2}}^{2} \frac{d x}{x^{2} \cdot \frac{1}{x} \cdot \sqrt{x^{2}-1}}=\int_{\sqrt{2}}^{2} \frac{d x}{x^{2} \cdot \sqrt{1-\frac{1}{x^{2}}}}=-\int_{\sqrt{2}}^{2} \frac{d\left(\frac{1}{x}\right)}{\sqrt{1-\frac{1}{x^{2}}}}= \\ = & \in...
\frac{\pi}{12}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,886
## Problem Statement Calculate the definite integral: $$ \int_{1}^{e} \frac{x^{2}+\ln x^{2}}{x} d x $$
## Solution $$ \begin{aligned} & \int_{1}^{e} \frac{x^{2}+\ln x^{2}}{x} d x=\int_{1}^{e} \frac{x^{2}}{x} d x+\int_{1}^{e} \frac{\ln x^{2}}{x} d x= \\ & =\int_{1}^{e} x \cdot d x+\int_{1}^{e} \ln x^{2} \cdot d(\ln x)=\left.\frac{x^{2}}{2}\right|_{1} ^{e}+\int_{1}^{e} 2 \ln x \cdot d(\ln x)= \\ & =\frac{e^{2}}{2}-\frac{...
\frac{e^{2}+1}{2}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,887
## Problem Statement Calculate the definite integral: $$ \int_{0}^{1} \frac{x}{\sqrt{x^{4}+x^{2}+1}} d x $$
## Solution $$ \begin{aligned} & \int_{0}^{1} \frac{x}{\sqrt{x^{4}+x^{2}+1}} d x=\int_{0}^{1} \frac{\frac{1}{2} \cdot d\left(x^{2}+\frac{1}{2}\right)}{\sqrt{\left(x^{2}+\frac{1}{2}\right)^{2}+\frac{3}{4}}}=\frac{1}{2} \cdot \ln \left|x^{2}+\frac{1}{2}+\sqrt{\left(x^{2}+\frac{1}{2}\right)^{2}+\frac{3}{4}}\right|_{0}^{1...
\ln\sqrt{\frac{3+2\sqrt{3}}{3}}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,888
## Problem Statement Calculate the definite integral: $$ \int_{0}^{1} \frac{x^{3} d x}{\left(x^{2}+1\right)^{2}} $$
## Solution $$ \begin{aligned} & \int_{0}^{1} \frac{x^{3}}{\left(x^{2}+1\right)^{2}} d x=\int_{0}^{1} \frac{x\left(x^{2}+1\right)-x}{\left(x^{2}+1\right)^{2}} d x=\int_{0}^{1} \frac{x}{x^{2}+1} d x-\int_{0}^{1} \frac{x}{\left(x^{2}+1\right)^{2}} d x= \\ & =\frac{1}{2} \cdot \int_{0}^{1} \frac{d\left(x^{2}+1\right)}{x^...
\frac{\ln4-1}{4}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,889
## Problem Statement Calculate the definite integral: $$ \int_{0}^{\frac{\pi}{4}} \operatorname{tg} x \cdot \ln (\cos x) d x $$
## Solution $$ \int_{0}^{\frac{\pi}{4}} \operatorname{tg} x \cdot \ln (\cos x) d x= $$ Substitution: $$ \begin{aligned} & y=\ln \cos x \\ & d y=\frac{1}{\cos x} \cdot(-\sin x) \cdot d x=-\operatorname{tg} x \cdot d x \\ & x=0 \Rightarrow y=\ln \cos 0=\ln 1=0 \\ & x=\frac{\pi}{4} \Rightarrow y=\ln \cos \frac{\pi}{4}=...
-\frac{1}{2}\cdot\ln^{2}\frac{\sqrt{2}}{2}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,890
## Problem Statement Calculate the definite integral: $$ \int_{-1}^{0} \frac{\tan(x+1)}{\cos^2(x+1)} \, dx $$
## Solution $$ \begin{aligned} & \int_{-1}^{0} \frac{\tan(x+1)}{\cos^2(x+1)} \, dx = \int_{-1}^{0} \tan(x+1) \cdot d(\tan(x+1)) = \left. \frac{\tan^2(x+1)}{2} \right|_{-1}^{0} = \\ & = \frac{\tan^2(0+1)}{2} - \frac{\tan^2(-1+1)}{2} = \frac{\tan^2 1}{2} - \frac{\tan^2 0}{2} = \frac{\tan^2 1}{2} - \frac{0^2}{2} = \frac{...
\frac{\tan^21}{2}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,891
## Problem Statement Calculate the definite integral: $$ \int_{0}^{\frac{1}{\sqrt{2}}} \frac{(\arccos x)^{3}-1}{\sqrt{1-x^{2}}} d x $$
## Solution $$ \begin{aligned} & \int_{0}^{\frac{1}{\sqrt{2}}} \frac{\arccos ^{3} x-1}{\sqrt{1-x^{2}}} d x=\int_{0}^{\frac{1}{\sqrt{2}}} \frac{\arccos ^{3} x}{\sqrt{1-x^{2}}} d x+\int_{0}^{\frac{1}{\sqrt{2}}} \frac{-d x}{\sqrt{1-x^{2}}}= \\ & =\int_{0}^{\frac{1}{\sqrt{2}}}-(\arccos x)^{3} d(\arccos x)+\left.\arccos x\...
\frac{15\pi^{4}}{2^{10}}-\frac{\pi}{4}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,892
## Problem Statement Calculate the definite integral: $$ \int_{\pi}^{2 \pi} \frac{1-\cos x}{(x-\sin x)^{2}} d x $$
## Solution $$ \begin{aligned} & \int_{\pi}^{2 \pi} \frac{1-\cos x}{(x-\sin x)^{2}} d x=\int_{\pi}^{2 \pi} \frac{d(x-\sin x)}{(x-\sin x)^{2}}=-\left.\frac{1}{x-\sin x}\right|_{\pi} ^{2 \pi}= \\ & =-\frac{1}{2 \pi-\sin (2 \pi)}+\frac{1}{\pi-\sin \pi}=-\frac{1}{2 \pi-0}+\frac{1}{\pi-0}=-\frac{1}{2 \pi}+\frac{2}{2 \pi}=\...
\frac{1}{2\pi}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,893
## Problem Statement Calculate the definite integral: $$ \int_{0}^{\frac{\pi}{4}} \frac{\sin x - \cos x}{(\cos x + \sin x)^{5}} d x $$
## Solution $$ \begin{aligned} & \int_{0}^{\frac{\pi}{4}} \frac{\sin x-\cos x}{(\cos x+\sin x)^{5}} d x=-\int_{0}^{\frac{\pi}{4}} \frac{d(\cos x+\sin x)}{(\cos x+\sin x)^{5}}=\left.\frac{1}{4} \cdot \frac{1}{(\cos x+\sin x)^{4}}\right|_{0} ^{\frac{\pi}{4}}= \\ & =\frac{1}{4} \cdot \frac{1}{\left(\cos \frac{\pi}{4}+\si...
-\frac{3}{16}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,894
## Condition of the problem Calculate the definite integral: $$ \int_{\frac{\pi}{4}}^{\frac{\pi}{2}} \frac{x \cdot \cos x+\sin x}{(x \cdot \sin x)^{2}} d x $$
## Solution $$ \int_{\frac{\pi}{4}}^{\frac{\pi}{2}} \frac{x \cdot \cos x+\sin x}{(x \cdot \sin x)^{2}} d x= $$ Substitution: $$ \begin{aligned} & y=x \cdot \sin x \\ & d y=(\sin x+x \cdot \cos x) d x \\ & x=\frac{\pi}{4} \Rightarrow y=\frac{\pi}{4} \cdot \sin \frac{\pi}{4}=\frac{\sqrt{2} \pi}{8} \\ & x=\frac{\pi}{2}...
\frac{4\sqrt{2}-2}{\pi}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,895
## Problem Statement Calculate the definite integral: $$ \int_{0}^{1} \frac{x^{3}+x}{x^{4}+1} d x $$
## Solution $$ \begin{aligned} & \int_{0}^{1} \frac{x^{3}+x}{x^{4}+1} d x=\int_{0}^{1} \frac{x^{3}}{x^{4}+1} d x+\int \frac{x}{x^{4}+1} d x= \\ & =\frac{1}{4} \cdot \int_{0}^{1} \frac{1}{x^{4}+1} d\left(x^{4}+1\right)+\frac{1}{2} \cdot \int_{0}^{1} \frac{1}{x^{4}+1} d\left(x^{2}\right)= \\ & =\frac{1}{4} \cdot \ln \le...
\frac{\ln4+\pi}{8}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,896
## Problem Statement Calculate the definite integral: $$ \int_{\sqrt{2}}^{\sqrt{3}} \frac{x}{\sqrt{x^{4}-x^{2}-1}} d x $$
## Solution $$ \begin{aligned} & \int_{\sqrt{2}}^{\sqrt{3}} \frac{x}{\sqrt{x^{4}-x^{2}-1}} d x=\int_{\sqrt{2}}^{\sqrt{3}} \frac{\frac{1}{2} \cdot d\left(x^{2}-\frac{1}{2}\right)}{\sqrt{\left(x^{2}-\frac{1}{2}\right)^{2}-\frac{5}{4}}}=\frac{1}{2} \cdot \ln \left|x^{2}-\frac{1}{2}+\sqrt{\left(x^{2}-\frac{1}{2}\right)^{2...
\ln\sqrt{\frac{5+2\sqrt{5}}{5}}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,897
## Problem Statement Calculate the definite integral: $$ \int_{2}^{9} \frac{x}{\sqrt[3]{x-1}} d x $$
## Solution $$ \begin{aligned} & \int_{2}^{9} \frac{x}{\sqrt[3]{x-1}} d x=\int_{2}^{9} \frac{x-1+1}{\sqrt[3]{x-1}} d x=\int_{2}^{9} \sqrt[3]{(x-1)^{2}} d x+\int_{2}^{9} \frac{1}{\sqrt[3]{x-1}} d x= \\ & =\left.\frac{3}{5} \cdot \sqrt[3]{(x-1)^{5}}\right|_{2} ^{9}+\left.\frac{3}{2} \cdot \sqrt[3]{(x-1)^{2}}\right|_{2} ...
23.1
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,898
## Condition of the problem Prove that $\lim _{n \rightarrow \infty} a_{n}=a_{\text {(specify }} N(\varepsilon)$ ). $a_{n}=\frac{2 n-1}{2-3 n}, a=-\frac{2}{3}$
## Solution By the definition of the limit: $\forall \varepsilon>0: \exists N(\varepsilon) \in \mathbb{N}: \forall n: n \geq N(\varepsilon):\left|a_{n}-a\right| \\ & \left|\frac{6 n-3+4-6 n}{3(2-3 n)}\right| \\ & \left.\frac{1}{3(2-3 n)} \right\rvert\, \\ & \left|\frac{1}{3(3 n-2)}\right| \\ & \frac{1}{3(3 n-2)} \\ &...
N(\varepsilon)=[\frac{1+15\varepsilon}{9\varepsilon}]
Calculus
proof
Yes
Yes
olympiads
false
46,899
## Problem Statement Calculate the limit of the numerical sequence: $$ \lim _{n \rightarrow \infty} \frac{(n+7)^{3}-(n+2)^{3}}{(3 n+2)^{2}+(4 n+1)^{2}} $$
## Solution $$ \begin{aligned} & \lim _{n \rightarrow \infty} \frac{(n+7)^{3}-(n+2)^{3}}{(3 n+2)^{2}+(4 n+1)^{2}}=\lim _{n \rightarrow \infty} \frac{n^{3}+3 \cdot 7 \cdot n^{2}+3 \cdot 7^{2} \cdot n+7^{3}-n^{3}-3 \cdot 2 \cdot n^{2}-3 \cdot 2^{2} \cdot n-2^{3}}{(3 n+2)^{2}+(4 n+1)^{2}}= \\ & =\lim _{n \rightarrow \inf...
\frac{3}{5}
Algebra
math-word-problem
Yes
Yes
olympiads
false
46,900
## Problem Statement Calculate the limit of the numerical sequence: $$ \lim _{n \rightarrow \infty} \frac{\sqrt{n+3}-\sqrt[3]{8 n^{3}+3}}{\sqrt[4]{n+4}-\sqrt[5]{n^{5}+5}} $$
## Solution $$ \begin{aligned} & \lim _{n \rightarrow \infty} \frac{\sqrt{n+3}-\sqrt[3]{8 n^{3}+3}}{\sqrt[4]{n+4}-\sqrt[5]{n^{5}+5}}=\lim _{n \rightarrow \infty} \frac{\frac{1}{n}\left(\sqrt{n+3}-\sqrt[3]{8 n^{3}+3}\right)}{\frac{1}{n}\left(\sqrt[4]{n+4}-\sqrt[5]{n^{5}+5}\right)}= \\ & =\lim _{n \rightarrow \infty} \f...
2
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,901
## Problem Statement Calculate the limit of the numerical sequence: $$ \lim _{n \rightarrow \infty} \frac{\sqrt{\left(n^{3}+1\right)\left(n^{2}+3\right)}-\sqrt{n\left(n^{4}+2\right)}}{2 \sqrt{n}} $$
## Solution $$ \begin{aligned} & \lim _{n \rightarrow \infty} \frac{\sqrt{\left(n^{3}+1\right)\left(n^{2}+3\right)}-\sqrt{n\left(n^{4}+2\right)}}{2 \sqrt{n}}= \\ & =\lim _{n \rightarrow \infty} \frac{\left(\sqrt{\left(n^{3}+1\right)\left(n^{2}+3\right)}-\sqrt{n\left(n^{4}+2\right)}\right)\left(\sqrt{\left(n^{3}+1\righ...
\frac{3}{4}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,902
## Problem Statement Calculate the limit of the numerical sequence: $\lim _{n \rightarrow \infty} \frac{(2 n+1)!+(2 n+2)!}{(2 n+3)!-(2 n+2)!}$
## Solution $\lim _{n \rightarrow \infty} \frac{(2 n+1)!+(2 n+2)!}{(2 n+3)!-(2 n+2)!}=\lim _{n \rightarrow \infty} \frac{(2 n+1)!+(2 n+2)!}{(2 n+3) \cdot(2 n+2)!-(2 n+2)!}=$ $$ =\lim _{n \rightarrow \infty} \frac{(2 n+1)!+(2 n+2)!}{(2 n+2)!((2 n+3)-1)}=\lim _{n \rightarrow \infty} \frac{(2 n+1)!+(2 n+2)!}{(2 n+2)!\cd...
0
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,903
## Problem Statement Calculate the limit of the numerical sequence: $\lim _{n \rightarrow \infty}\left(\frac{10 n-3}{10 n-1}\right)^{5 n}$
## Solution $$ \begin{aligned} & \lim _{n \rightarrow \infty}\left(\frac{10 n-3}{10 n-1}\right)^{5 n}=\lim _{n \rightarrow \infty}\left(\frac{10 n-1}{10 n-3}\right)^{-5 n}= \\ & =\lim _{n \rightarrow \infty}\left(\frac{10 n-3+2}{10 n-3}\right)^{-5 n}=\lim _{n \rightarrow \infty}\left(1+\frac{2}{10 n-3}\right)^{-5 n}= ...
\frac{1}{e}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,904
## Condition of the problem Prove that (find $\delta(\varepsilon)$ : $$ \lim _{x \rightarrow 5} \frac{5 x^{2}-24 x-5}{x-5}=26 $$
## Solution According to the definition of the limit of a function by Cauchy: If a function \( f: M \subset \mathbb{R} \rightarrow \mathbb{R} \) and \( a \in M' \) is a limit point of the set \( M \). The number ![](https://cdn.mathpix.com/cropped/2024_05_22_42745aa634bb73565023g-04.jpg?height=81&width=1491&top_left...
\delta(\varepsilon)=\frac{\varepsilon}{5}
Calculus
proof
Yes
Yes
olympiads
false
46,905
## Condition of the problem Prove that the function $f(x)_{\text {is continuous at the point }} x_{0}$ (find $\delta(\varepsilon)$ ): $f(x)=2 x^{2}-3, x_{0}=4$
## Solution By definition, the function $f(x)_{\text {is continuous at the point }} x=x_{0}$, if $\forall \varepsilon>0: \exists \delta(\varepsilon)>0:$. $$ \left|x-x_{0}\right|0_{\text {there exists such }} \delta(\varepsilon)>0$, such that $\left|f(x)-f\left(x_{0}\right)\right|<\varepsilon$ when $\left|x-x_{0}\righ...
proof
Calculus
proof
Yes
Yes
olympiads
false
46,906
## Problem Statement Calculate the limit of the function: $\lim _{x \rightarrow 2} \frac{x^{3}-3 x-2}{x-2}$
## Solution $\lim _{x \rightarrow 2} \frac{x^{3}-3 x-2}{x-2}=\left\{\frac{0}{0}\right\}=\lim _{x \rightarrow 2} \frac{(x-2)\left(x^{2}+2 x+1\right)}{x-2}=$ $=\lim _{x \rightarrow 2}\left(x^{2}+2 x+1\right)=2^{2}+2 \cdot 2+1=4+4+1=9$ ## Problem Kuznetsov Limits 10-20
9
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,907
## Problem Statement Calculate the limit of the function: $\lim _{x \rightarrow \frac{1}{3}} \frac{\sqrt[3]{\frac{x}{9}}-\frac{1}{3}}{\sqrt{\frac{1}{3}+x}-\sqrt{2 x}}$
## Solution $\lim _{x \rightarrow \frac{1}{3}} \frac{\sqrt[3]{\frac{x}{9}}-\frac{1}{3}}{\sqrt{\frac{1}{3}+x}-\sqrt{2 x}}=\lim _{x \rightarrow \frac{1}{3}} \frac{\left(\sqrt[3]{\frac{x}{9}}-\frac{1}{3}\right)\left(\sqrt[3]{\left(\frac{x}{9}\right)^{2}}+\sqrt[3]{\frac{x}{9}} \cdot \frac{1}{3}+\left(\frac{1}{3}\right)^{2...
-\frac{2}{3}\sqrt{\frac{2}{3}}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,908
## Problem Statement Calculate the limit of the function: $$ \lim _{x \rightarrow 0} \frac{\sin (5(x+\pi))}{e^{3 x}-1} $$
## Solution We will use the substitution of equivalent infinitesimals: $e^{3 x}-1 \sim 3 x$, as $x \rightarrow 0(3 x \rightarrow 0)$ $\sin 5 x \sim 5 x$, as $x \rightarrow 0(5 x \rightarrow 0)$ We get: $$ \begin{aligned} & \lim _{x \rightarrow 0} \frac{\sin (5(x+\pi))}{e^{3 x}-1}=\left\{\frac{0}{0}\right\}=\lim _{...
-\frac{5}{3}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,909
## Problem Statement Calculate the limit of the function: $\lim _{x \rightarrow 2} \frac{\ln \left(9-2 x^{2}\right)}{\sin 2 \pi x}$
## Solution Substitution: $x=y+2 \Rightarrow y=x-2$ $x \rightarrow 2 \Rightarrow y \rightarrow 0$ We get: $$ \begin{aligned} & \lim _{x \rightarrow 2} \frac{\ln \left(9-2 x^{2}\right)}{\sin 2 \pi x}=\lim _{y \rightarrow 0} \frac{\ln \left(9-2(y+2)^{2}\right)}{\sin 2 \pi(y+2)}= \\ & =\lim _{y \rightarrow 0} \frac{\...
-\frac{4}{\pi}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,910
## Problem Statement Calculate the limit of the function: $\lim _{x \rightarrow-2} \frac{\tan \left(e^{x+2}-e^{x^{2}-4}\right)}{\tan x+\tan 2}$
## Solution Substitution: $x=y-2 \Rightarrow y=x+2$ $x \rightarrow-2 \Rightarrow y \rightarrow 0$ We get: $$ \begin{aligned} & \lim _{x \rightarrow-2} \frac{\tan\left(e^{x+2}-e^{x^{2}-4}\right)}{\tan x+\tan 2}=\lim _{y \rightarrow 0} \frac{\tan\left(e^{(y-2)+2}-e^{(y-2)^{2}-4}\right)}{\tan(y-2)+\tan 2}= \\ & =\lim ...
5\cos^{2}2
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,911
## Problem Statement Calculate the limit of the function: $\lim _{x \rightarrow 0} \frac{e^{2 x}-e^{-5 x}}{2 \sin x-\tan x}$
## Solution $\lim _{x \rightarrow 0} \frac{e^{2 x}-e^{-5 x}}{2 \sin x-\tan x}=\lim _{x \rightarrow 0} \frac{\left(e^{2 x}-1\right)-\left(e^{-5 x}-1\right)}{2 \sin x-\tan x}=$ $=\lim _{x \rightarrow 0} \frac{\frac{1}{x}\left(\left(e^{2 x}-1\right)-\left(e^{-5 x}-1\right)\right)}{\frac{1}{x}(2 \sin x-\tan x)}=$ $=\frac{...
7
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,912
## Problem Statement Calculate the limit of the function: $\lim _{x \rightarrow 0} \frac{\sqrt{x+2}-\sqrt{2}}{\sin 3 x}$
## Solution $\lim _{x \rightarrow 0} \frac{\sqrt{x+2}-\sqrt{2}}{\sin 3 x}=$ $\sin 3 x \sim 3 x$, as $x \rightarrow 0(3 x \rightarrow 0)$ We get: $$ \begin{aligned} & =\lim _{x \rightarrow 0} \frac{\sqrt{x+2}-\sqrt{2}}{3 x}= \\ & =\lim _{x \rightarrow 0} \frac{(\sqrt{x+2}-\sqrt{2})(\sqrt{x+2}+\sqrt{2})}{3 x(\sqrt{x+2...
\frac{1}{6\sqrt{2}}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,913
## Problem Statement Calculate the limit of the function: $\lim _{x \rightarrow 0} \sqrt[x^{2}]{2-\cos x}$
## Solution $\lim _{x \rightarrow 0} \sqrt[x^{2}]{2-\cos x}=\lim _{x \rightarrow 0}(2-\cos x)^{\frac{1}{x^{2}}}=$ $=\lim _{x \rightarrow 0}\left(e^{\ln (2-\cos x)}\right)^{\frac{1}{x^{2}}}=\lim _{x \rightarrow 0} e^{\frac{\ln (2-\cos x)}{x^{2}}}=$ $=\exp \left\{\lim _{x \rightarrow 0} \frac{\ln (1+(1-\cos x))}{x^{2}...
\sqrt{e}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,914
## Problem Statement Calculate the limit of the function: $\lim _{x \rightarrow \frac{\pi}{2}}(1+\cos 3 x)^{\sec x}$
## Solution $\lim _{x \rightarrow \frac{\pi}{2}}(1+\cos 3 x)^{\sec x}=\lim _{x \rightarrow \frac{\pi}{2}}(1+\cos 3 x)^{\frac{1}{\cos x}}=$ Substitution: $x=y+\frac{\pi}{2} \Rightarrow y=x-\frac{\pi}{2}$ $x \rightarrow \frac{\pi}{2} \Rightarrow y \rightarrow 0$ We get: $=\lim _{y \rightarrow 0}\left(1+\cos 3\left(...
e^{-3}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,916
## Problem Statement Calculate the limit of the function: $\lim _{x \rightarrow \pi}(x+\sin x)^{\sin x+x}$
## Solution $\lim _{x \rightarrow \pi}(x+\sin x)^{\sin x+x}=(\pi+\sin \pi)^{\sin \pi+\pi}=(\pi+0)^{0+\pi}=\pi^{\pi}$ ## Problem Kuznetsov Limits 20-20
\pi^{\pi}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,917
## Problem Statement Calculate the limit of the function: $\lim _{x \rightarrow 0} \frac{2+\ln \left(e+x \sin \left(\frac{1}{x}\right)\right)}{\cos x+\sin x}$
## Solution Since $\sin \left(\frac{1}{x}\right)_{\text {- is bounded as }} x \rightarrow 0$, then $x \sin \left(\frac{1}{x}\right) \rightarrow 0 \quad$ as $x \rightarrow 0$ Then: $\lim _{x \rightarrow 0} \frac{2+\ln \left(e+x \sin \left(\frac{1}{x}\right)\right)}{\cos x+\sin x}=\frac{2+\ln (e+0)}{\cos 0+\sin 0}=\f...
3
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,918
## Problem Statement Calculate the definite integral: $$ \int_{\frac{\pi}{2}}^{2 \operatorname{arctan} 2} \frac{d x}{\sin ^{2} x(1-\cos x)} $$
## Solution We will use the universal substitution: $$ t=\operatorname{tg} \frac{x}{2} $$ From which: $$ \begin{aligned} & \sin x=\frac{2 t}{1+t^{2}}, \cos x=\frac{1-t^{2}}{1+t^{2}}, d x=\frac{2 d t}{1+t^{2}} \\ & x=\frac{\pi}{2} \Rightarrow t=\operatorname{tg} \frac{\left(\frac{\pi}{2}\right)}{2}=\operatorname{tg}...
\frac{55}{96}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,919
## Problem Statement Calculate the definite integral: $$ \int_{0}^{\frac{\pi}{2}} \frac{\cos x \, dx}{2+\cos x} $$
## Solution We will use the universal substitution: $$ t=\operatorname{tg} \frac{x}{2} $$ From which: $$ \begin{aligned} & \cos x=\frac{1-t^{2}}{1+t^{2}}, d x=\frac{2 d t}{1+t^{2}} \\ & x=0 \Rightarrow t=\operatorname{tg} \frac{0}{2}=\operatorname{tg} 0=0 \\ & x=\frac{\pi}{2} \Rightarrow t=\operatorname{tg} \frac{\...
\frac{(9-4\sqrt{3})\pi}{18}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,920
## Problem Statement Calculate the definite integral: $$ \int_{\frac{\pi}{2}}^{2 \operatorname{arctan} 2} \frac{d x}{\sin ^{2} x(1+\cos x)} $$
## Solution We will use the universal substitution: $$ t=\operatorname{tg} \frac{x}{2} $$ From which: $$ \begin{aligned} & \sin x=\frac{2 t}{1+t^{2}}, \cos x=\frac{1-t^{2}}{1+t^{2}}, d x=\frac{2 d t}{1+t^{2}} \\ & x=\frac{\pi}{2} \Rightarrow t=\operatorname{tg} \frac{\left(\frac{\pi}{2}\right)}{2}=\operatorname{tg}...
\frac{29}{24}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,921
## Condition of the problem Calculate the definite integral: $$ \int_{2 \operatorname{arctg} \frac{1}{2}}^{\frac{\pi}{2}} \frac{\cos x d x}{(1-\cos x)^{3}} $$
## Solution We will use the universal substitution: $$ t=\operatorname{tg} \frac{x}{2} $$ From which: $$ \begin{aligned} & \cos x=\frac{1-t^{2}}{1+t^{2}}, d x=\frac{2 d t}{1+t^{2}} \\ & x=2 \operatorname{arctg} \frac{1}{2} \Rightarrow t=\operatorname{tg} \frac{2 \operatorname{arctg} \frac{1}{2}}{2}=\operatorname{tg...
1.3
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,922
## Problem Statement Calculate the definite integral: $$ \int_{0}^{\frac{\pi}{2}} \frac{\cos x - \sin x}{(1 + \sin x)^{2}} d x $$
## Solution We will use the universal substitution: $$ t=\operatorname{tg} \frac{x}{2} $$ From which: $$ \begin{aligned} & \sin x=\frac{2 t}{1+t^{2}}, \cos x=\frac{1-t^{2}}{1+t^{2}}, d x=\frac{2 d t}{1+t^{2}} \\ & x=0 \Rightarrow t=\operatorname{tg} \frac{0}{2}=\operatorname{tg} 0=0 \\ & x=\frac{\pi}{2} \Rightarrow...
\frac{1}{6}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,923
## Problem Statement Calculate the definite integral: $$ \int_{2 \operatorname{arctan} 2}^{2 \operatorname{arctan} 3} \frac{d x}{\cos x(1-\cos x)} $$
## Solution We will use the universal substitution: $$ t=\operatorname{tg} \frac{x}{2} $$ From which: $$ \begin{aligned} & \cos x=\frac{1-t^{2}}{1+t^{2}}, d x=\frac{2 d t}{1+t^{2}} \\ & x=2 \operatorname{arctg} 2 \Rightarrow t=\operatorname{tg} \frac{2 \operatorname{arctg} 2}{2}=\operatorname{tg}(\operatorname{arct...
\frac{1}{6}+\ln2-\ln3
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,924
## Problem Statement Calculate the definite integral: $$ \int_{2 \operatorname{arctg} \frac{1}{3}}^{2 \operatorname{arctg} \frac{1}{2}} \frac{d x}{\sin x(1-\sin x)} $$
## Solution We will use the universal substitution: $$ t=\operatorname{tg} \frac{x}{2} $$ From which: $$ \begin{aligned} & \sin x=\frac{2 t}{1+t^{2}}, d x=\frac{2 d t}{1+t^{2}} \\ & x=2 \operatorname{arctg} \frac{1}{3} \Rightarrow t=\operatorname{tg} \frac{2 \operatorname{arctg} \frac{1}{3}}{2}=\operatorname{tg}\le...
\ln3-\ln2+1
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,925
## Condition of the problem Calculate the definite integral: $$ \int_{2 \operatorname{arctg} \frac{1}{2}}^{\frac{\pi}{2}} \frac{d x}{(1+\sin x-\cos x)^{2}} $$
## Solution We will use the universal substitution: $$ t=\operatorname{tg} \frac{x}{2} $$ From which: $$ \begin{aligned} & \sin x=\frac{2 t}{1+t^{2}}, \cos x=\frac{1-t^{2}}{1+t^{2}}, d x=\frac{2 d t}{1+t^{2}} \\ & x=2 \operatorname{arctg} \frac{1}{2} \Rightarrow t=\operatorname{tg} \frac{2 \operatorname{arctg} \fra...
\frac{1}{2}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,926
## Problem Statement Calculate the definite integral: $$ \int_{0}^{\frac{\pi}{2}} \frac{\cos x d x}{5+4 \cos x} $$
## Solution We will use the universal substitution: $$ t=\operatorname{tg} \frac{x}{2} $$ From which: $$ \begin{aligned} & \cos x=\frac{1-t^{2}}{1+t^{2}}, d x=\frac{2 d t}{1+t^{2}} \\ & x=0 \Rightarrow t=\operatorname{tg} \frac{0}{2}=\operatorname{tg} 0=0 \\ & x=\frac{\pi}{2} \Rightarrow t=\operatorname{tg} \frac{\...
\frac{\pi}{8}-\frac{5}{6}\cdot\operatorname{arctg}\frac{1}{3}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,927
## Problem Statement Calculate the definite integral: $$ \int_{0}^{\frac{2 \pi}{3}} \frac{1+\sin x}{1+\cos x+\sin x} d x $$
## Solution We will use the universal substitution: $$ t=\operatorname{tg} \frac{x}{2} $$ From which: $$ \begin{aligned} & \sin x=\frac{2 t}{1+t^{2}}, \cos x=\frac{1-t^{2}}{1+t^{2}}, d x=\frac{2 d t}{1+t^{2}} \\ & x=0 \Rightarrow t=\operatorname{tg} \frac{0}{2}=\operatorname{tg} 0=0 \\ & x=\frac{2 \pi}{3} \Rightarr...
\frac{\pi}{3}+\ln2
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,928
## Problem Statement Calculate the definite integral: $$ \int_{\frac{\pi}{3}}^{\frac{\pi}{2}} \frac{\cos x \, dx}{1+\sin x-\cos x} $$
## Solution Let's use the universal substitution: $$ t=\operatorname{tg} \frac{x}{2} $$ From which: $$ \begin{aligned} & \sin x=\frac{2 t}{1+t^{2}}, \cos x=\frac{1-t^{2}}{1+t^{2}}, d x=\frac{2 d t}{1+t^{2}} \\ & x=\frac{\pi}{3} \Rightarrow t=\operatorname{tg} \frac{\left(\frac{\pi}{3}\right)}{2}=\operatorname{tg} \...
\frac{1}{2}\cdot\ln2-\frac{\pi}{12}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,929
## Problem Statement Calculate the definite integral: $$ \int_{0}^{\frac{\pi}{2}} \frac{(1+\cos x) d x}{1+\sin x+\cos x} $$
## Solution We will use the universal substitution: $$ t=\operatorname{tg} \frac{x}{2} $$ From which: $$ \begin{aligned} & \sin x=\frac{2 t}{1+t^{2}}, \cos x=\frac{1-t^{2}}{1+t^{2}}, d x=\frac{2 d t}{1+t^{2}} \\ & x=0 \Rightarrow t=\operatorname{tg} \frac{0}{2}=\operatorname{tg} 0=0 \\ & x=\frac{\pi}{2} \Rightarrow...
\frac{1}{2}\cdot\ln2+\frac{\pi}{4}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,930
## Problem Statement Calculate the definite integral: $$ \int_{0}^{\frac{\pi}{2}} \frac{\sin x \, dx}{1+\sin x+\cos x} $$
## Solution We will use the universal substitution: $$ t=\operatorname{tg} \frac{x}{2} $$ From which: $$ \begin{aligned} & \sin x=\frac{2 t}{1+t^{2}}, \cos x=\frac{1-t^{2}}{1+t^{2}}, d x=\frac{2 d t}{1+t^{2}} \\ & x=0 \Rightarrow t=\operatorname{tg} \frac{0}{2}=\operatorname{tg} 0=0 \\ & x=\frac{\pi}{2} \Rightarrow...
-\frac{1}{2}\cdot\ln2+\frac{\pi}{4}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,931
## Condition of the problem Calculate the definite integral: $$ \int_{0}^{2 \operatorname{arctan} \frac{1}{2}} \frac{1+\sin x}{(1-\sin x)^{2}} d x $$
## Solution We will use the universal substitution: $$ t=\operatorname{tg} \frac{x}{2} $$ From which: $$ \begin{aligned} & \sin x=\frac{2 t}{1+t^{2}}, d x=\frac{2 d t}{1+t^{2}} \\ & x=0 \Rightarrow t=\operatorname{tg} \frac{0}{2}=\operatorname{tg} 0=0 \\ & x=2 \operatorname{arctg} \frac{1}{2} \Rightarrow t=\operato...
\frac{26}{3}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,932
## Problem Statement Calculate the definite integral: $$ \int_{0}^{\frac{\pi}{2}} \frac{\cos x \, dx}{1+\sin x+\cos x} $$
## Solution We will use the universal substitution: $$ t=\operatorname{tg} \frac{x}{2} $$ From which: $$ \begin{aligned} & \sin x=\frac{2 t}{1+t^{2}}, \cos x=\frac{1-t^{2}}{1+t^{2}}, d x=\frac{2 d t}{1+t^{2}} \\ & x=0 \Rightarrow t=\operatorname{tg} \frac{0}{2}=\operatorname{tg} 0=0 \\ & x=\frac{\pi}{2} \Rightarrow...
\frac{\pi}{4}-\frac{1}{2}\cdot\ln2
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,933
## Problem Statement Calculate the definite integral: $$ \int_{0}^{2 \operatorname{arctan} \frac{1}{3}} \frac{\cos x d x}{(1-\sin x)(1+\cos x)} $$
## Solution We will use the universal substitution: $$ t=\operatorname{tg} \frac{x}{2} $$ From which: $$ \begin{aligned} & \sin x=\frac{2 t}{1+t^{2}}, \cos x=\frac{1-t^{2}}{1+t^{2}}, d x=\frac{2 d t}{1+t^{2}} \\ & x=0 \Rightarrow t=\operatorname{tg} \frac{0}{2}=\operatorname{tg} 0=0 \\ & x=2 \operatorname{arctg} \f...
-\frac{1}{3}-2\ln\frac{2}{3}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,934
## Problem Statement Calculate the definite integral: $$ \int_{-\frac{2 \pi}{3}}^{0} \frac{\cos x \, dx}{1+\cos x-\sin x} $$
## Solution We will use the universal substitution: $$ t=\operatorname{tg} \frac{x}{2} $$ From which: $$ \begin{aligned} & \sin x=\frac{2 t}{1+t^{2}}, \cos x=\frac{1-t^{2}}{1+t^{2}}, d x=\frac{2 d t}{1+t^{2}} \\ & x=-\frac{2 \pi}{3} \Rightarrow t=\operatorname{tg} \frac{\left(-\frac{2 \pi}{3}\right)}{2}=\operatorna...
\frac{\pi}{3}-\ln2
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,935
## Problem Statement Calculate the definite integral: $$ \int_{-\frac{\pi}{2}}^{0} \frac{\cos x \, dx}{(1+\cos x-\sin x)^{2}} $$
## Solution We will use the universal substitution: $$ t=\operatorname{tg} \frac{x}{2} $$ From which: $$ \begin{aligned} & \sin x=\frac{2 t}{1+t^{2}}, \cos x=\frac{1-t^{2}}{1+t^{2}}, d x=\frac{2 d t}{1+t^{2}} \\ & x=-\frac{\pi}{2} \Rightarrow t=\operatorname{tg} \frac{\left(-\frac{\pi}{2}\right)}{2}=\operatorname{t...
-\frac{1}{2}+\ln2
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,936
## Problem Statement Calculate the definite integral: $$ \int_{0}^{\frac{\pi}{2}} \frac{\cos x \, dx}{(1+\cos x+\sin x)^{2}} $$
## Solution We will use the universal substitution: $$ t=\operatorname{tg} \frac{x}{2} $$ From which: $$ \begin{aligned} & \sin x=\frac{2 t}{1+t^{2}}, \cos x=\frac{1-t^{2}}{1+t^{2}}, d x=\frac{2 d t}{1+t^{2}} \\ & x=0 \Rightarrow t=\operatorname{tg} \frac{0}{2}=\operatorname{tg} 0=0 \\ & x=\frac{\pi}{2} \Rightarrow...
-\frac{1}{2}+\ln2
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,937
## Problem Statement Calculate the definite integral: $$ \int_{0}^{2 \operatorname{arctan} \frac{1}{2}} \frac{(1-\sin x) d x}{\cos x(1+\cos x)} $$
## Solution We will use the universal substitution: $$ t=\operatorname{tg} \frac{x}{2} $$ From which: $$ \begin{aligned} & \sin x=\frac{2 t}{1+t^{2}}, \cos x=\frac{1-t^{2}}{1+t^{2}}, d x=\frac{2 d t}{1+t^{2}} \\ & x=0 \Rightarrow t=\operatorname{tg} \frac{0}{2}=\operatorname{tg} 0=0 \\ & x=2 \operatorname{arctg} \f...
-\frac{1}{2}+2\ln\frac{3}{2}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,938
## Problem Statement Calculate the definite integral: $$ \int_{0}^{\frac{\pi}{2}} \frac{\sin x \, dx}{(1+\sin x)^{2}} $$
## Solution We will use the universal substitution: $$ t=\operatorname{tg} \frac{x}{2} $$ From which: $$ \begin{aligned} & \sin x=\frac{2 t}{1+t^{2}}, d x=\frac{2 d t}{1+t^{2}} \\ & x=0 \Rightarrow t=\operatorname{tg} \frac{0}{2}=\operatorname{tg} 0=0 \\ & x=\frac{\pi}{2} \Rightarrow t=\operatorname{tg} \frac{\left...
\frac{1}{3}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,939
## Problem Statement Calculate the definite integral: $$ \int_{0}^{\frac{\pi}{2}} \frac{\sin x d x}{(1+\cos x+\sin x)^{2}} $$
## Solution We will use the universal substitution: $$ t=\operatorname{tg} \frac{x}{2} $$ From which: $$ \begin{aligned} & \sin x=\frac{2 t}{1+t^{2}}, \cos x=\frac{1-t^{2}}{1+t^{2}}, d x=\frac{2 d t}{1+t^{2}} \\ & x=0 \Rightarrow t=\operatorname{tg} \frac{0}{2}=\operatorname{tg} 0=0 \\ & x=\frac{\pi}{2} \Rightarrow...
\ln2-\frac{1}{2}
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,940
## Problem Statement Calculate the definite integral: $$ \int_{-\frac{\pi}{2}}^{0} \frac{\sin x d x}{(1+\cos x-\sin x)^{2}} $$
## Solution We will use the universal substitution: $$ t=\operatorname{tg} \frac{x}{2} $$ From which: $$ \begin{aligned} & \sin x=\frac{2 t}{1+t^{2}}, \cos x=\frac{1-t^{2}}{1+t^{2}}, d x=\frac{2 d t}{1+t^{2}} \\ & x=-\frac{\pi}{2} \Rightarrow t=\operatorname{tg} \frac{\left(-\frac{\pi}{2}\right)}{2}=\operatorname{t...
\frac{1}{2}-\ln2
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,941
## Problem Statement Calculate the definite integral: $$ \int_{-\frac{2 \pi}{3}}^{0} \frac{\cos ^{2} x d x}{(1+\cos x-\sin x)^{2}} $$
## Solution We will use the universal substitution: $$ t=\operatorname{tg} \frac{x}{2} $$ From which: $$ \begin{aligned} & \sin x=\frac{2 t}{1+t^{2}}, \cos x=\frac{1-t^{2}}{1+t^{2}}, d x=\frac{2 d t}{1+t^{2}} \\ & x=-\frac{2 \pi}{3} \Rightarrow t=\operatorname{tg} \frac{\left(-\frac{2 \pi}{3}\right)}{2}=\operatorna...
\frac{\sqrt{3}}{2}-\ln2
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,942
## Problem Statement Calculate the definite integral: $$ \int_{0}^{\frac{\pi}{2}} \frac{\sin ^{2} x d x}{(1+\cos x+\sin x)^{2}} $$
## Solution We will use the universal substitution: $$ t=\operatorname{tg} \frac{x}{2} $$ From which: $$ \begin{aligned} & \sin x=\frac{2 t}{1+t^{2}}, \cos x=\frac{1-t^{2}}{1+t^{2}}, d x=\frac{2 d t}{1+t^{2}} \\ & x=0 \Rightarrow t=\operatorname{tg} \frac{0}{2}=\operatorname{tg} 0=0 \\ & x=\frac{\pi}{2} \Rightarrow...
\frac{1}{2}-\frac{1}{2}\cdot\ln2
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,943
## Problem Statement Calculate the definite integral: $$ \int_{0}^{\frac{2 \pi}{3}} \frac{\cos ^{2} x d x}{(1+\cos x+\sin x)^{2}} $$
## Solution We will use the universal substitution: $$ t=\operatorname{tg} \frac{x}{2} $$ From which: $$ \begin{aligned} & \sin x=\frac{2 t}{1+t^{2}}, \cos x=\frac{1-t^{2}}{1+t^{2}}, d x=\frac{2 d t}{1+t^{2}} \\ & x=0 \Rightarrow t=\operatorname{tg} \frac{0}{2}=\operatorname{tg} 0=0 \\ & x=\frac{2 \pi}{3} \Rightarr...
\frac{\sqrt{3}}{2}-\ln2
Calculus
math-word-problem
Yes
Yes
olympiads
false
46,944