Question
Evaluate the following integrals:
$\int\cos^5\text{x}\text{ dx}$

Answer

$\int\cos^5\text{x}\text{ dx}$
$=\int\cos^4\text{x}\cdot\cos\text{x}\text{ dx}$
$=\int(1-\sin^2\text{x})^2\cos\text{x}\text{ dx}$
Let $\sin\text{x}=\text{t}$
$\cos\text{x}\text{ dx}=\text{dt}$
Now, $\int(1-\sin^2\text{x})^2\cos\text{x}\text{ dx}$
$=\int(1-\text{t}^2)^2\text{ dt}$
$=\int(1+\text{t}^4-2\text{t}^2)\text{dt}$
$=\int\text{dt}+\int\text{t}^4\text{ dt}-2\int\text{t}^2\text{ dt}$
$=\text{t}+\frac{\text{t}^5}{5}-\frac{2\text{t}^3}{3}+\text{C}$
$=\sin\text{x}+\frac{\sin^5\text{x}}{5}-\frac{2}{3}\sin^3\text{x}+\text{C}$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

If D, E, F are the mid-points of side BC, CA and AB respectively of a triangle ABC, write the value of $\overrightarrow{\text{AD}}+\overrightarrow{\text{BE}}+\overrightarrow{\text{CF}}$.
For the following differntial equations verify that the accompanying function is a solution:
Differential equation Function
$\text{x}+\text{y}\frac{\text{dy}}{\text{dx}}=0$ $\text{y}=\pm\sqrt{\text{a}^2-\text{x}^2}$
Find $\frac{d y}{d x}$ if

$x=\cos ^{-1}\left(\frac{2 t}{1+t^2}\right), y=\sec ^{-1}\left(\sqrt{1+t^2}\right)$

Find the values of $c$ so that for all real $x$ the vectors $x c \hat{i}-6 \hat{j}+3 \hat{k}$ and $x \hat{i}+2 \hat{j}+2 c x \hat{k}$make an obtuse angle.
Differentiate the following w.r.t. x:

$\tan ^{-1}\left[\frac{\sqrt{x}(3-x)}{1-3 x}\right]$

In binomial distribution with five Bernoulli’s trials, the probability of one and two success are 0.4096 and 0.2048 respectively. Find the probability of success.
If $\vec{\text{a}}=2\hat{\text{i}}+2\hat{\text{j}}+3\hat{\text{k}},\vec{\text{b}}=-\hat{\text{i}}+2\hat{\text{j}}+\hat{\text{k}},$and $\vec{\text{c}}=3\hat{\text{i}}+\hat{\text{j}}$ are such that $\vec{\text{a}}+\lambda\vec{\text{b}}$ is perpendicular to $\vec{\text{c}},$ then find the value of $\lambda.$
Solve the following equation:
$(\text{e}^\text{y}+1)\cos\text{x dx}+\text{e}^\text{y}\sin\text{x}\text{dy}=0$
Let the p.m.f. (probablity mass function) of random variable $x$ be.
$\begin{array}{rlr}
P (x) & =\left(\frac{4}{x}\right)\left(\frac{5}{9}\right)^x\left(\frac{4}{9}\right)^{4-x}, & x=0,1,2,3,4 \\
& =0, & \text { otherwise }
\end{array}$
Find $E (x)$ and $\operatorname{Var}(x)$.
Solve graphically : 5y + 3 ≤ 0