NCERT Solutions
Class 12 - Mathematics Part-2 - Chapter 7: INTEGRALS
Exercise 7.3

Question. 1

Evaluate the integral \(\int \sin^2(2x+5)\,dx\).

Answer:

\(\frac{x}{2}-\frac{1}{8}\sin(4x+10)+C\)

Question. 2

Evaluate the integral \(\int \sin 3x\,\cos 4x\,dx\).

Answer:

\(-\frac{1}{14}\cos 7x+\frac{1}{2}\cos x+C\)

Question. 3

Evaluate the integral \(\int \cos 2x\,\cos 4x\,\cos 6x\,dx\).

Answer:

\(\frac{1}{4}\left[\frac{1}{12}\sin 12x + x + \frac{1}{8}\sin 8x + \frac{1}{4}\sin 4x\right]+C\)

Question. 4

Evaluate the integral \(\int \sin^3(2x+1)\,dx\).

Answer:

\(-\frac{1}{2}\cos(2x+1)+\frac{1}{6}\cos^3(2x+1)+C\)

Question. 5

Evaluate the integral \(\int \sin^3 x\,\cos^3 x\,dx\).

Answer:

\(\frac{1}{6}\cos^6 x-\frac{1}{4}\cos^4 x+C\)

Question. 6

Evaluate the integral \(\int \sin x\,\sin 2x\,\sin 3x\,dx\).

Answer:

\(\frac{1}{4}\left[\frac{1}{6}\cos 6x-\frac{1}{4}\cos 4x-\frac{1}{2}\cos 2x\right]+C\)

Question. 7

Evaluate the integral \(\int \sin 4x\,\sin 8x\,dx\).

Answer:

\(-\frac{1}{2}\left[\frac{1}{4}\sin 4x-\frac{1}{12}\sin 12x\right]+C\)

Question. 8

Evaluate the integral \(\int \frac{1-\cos x}{1+\cos x}\,dx\).

Answer:

\(2\tan\frac{x}{2}-x+C\)

Question. 9

Evaluate the integral \(\int \frac{\cos x}{1+\cos x}\,dx\).

Answer:

\(x-\tan\frac{x}{2}+C\)

Question. 10

Evaluate the integral \(\int \sin^4 x\,dx\).

Answer:

\(\frac{3x}{8}-\frac{1}{4}\sin 2x+\frac{1}{32}\sin 4x+C\)

Question. 11

Evaluate the integral \(\int \cos^4 2x\,dx\).

Answer:

\(\frac{3x}{8}+\frac{1}{8}\sin 4x+\frac{1}{64}\sin 8x+C\)

Question. 12

Evaluate the integral \(\int \frac{\sin^2 x}{1+\cos x}\,dx\).

Answer:

\(x-\sin x+C\)

Question. 13

Evaluate the integral \(\int \frac{\cos 2x-\cos 2\alpha}{\cos x-\cos \alpha}\,dx\).

Answer:

\(2(\sin x + x\cos\alpha)+C\)

Question. 14

Evaluate the integral \(\int \frac{\cos x-\sin x}{1+\sin 2x}\,dx\).

Answer:

\(-\frac{1}{\cos x+\sin x}+C\)

Question. 15

Evaluate the integral \(\int \tan^3 2x\,\sec 2x\,dx\).

Answer:

\(\frac{1}{6}\sec^3 2x-\frac{1}{2}\sec 2x+C\)

Question. 16

Evaluate the integral \(\int \tan^4 x\,dx\).

Answer:

\(\frac{1}{3}\tan^3 x-\tan x+x+C\)

Question. 17

Evaluate the integral \(\int \frac{\sin^3 x+\cos^3 x}{\sin^2 x\cos^2 x}\,dx\).

Answer:

\(\sec x-\cosec x+C\)

Question. 18

Evaluate the integral \(\int \frac{\cos 2x+2\sin^2 x}{\cos^2 x}\,dx\).

Answer:

\(\tan x+C\)

Question. 19

Evaluate the integral \(\int \frac{1}{\sin x\cos^3 x}\,dx\).

Answer:

\(\log|\tan x|+\frac{1}{2}\tan^2 x+C\)

Question. 20

Evaluate the integral \(\int \frac{\cos 2x}{(\cos x+\sin x)^2}\,dx\).

Answer:

\(\log|\cos x+\sin x|+C\)

Question. 21

Evaluate the integral \(\int \sin^{-1}(\cos x)\,dx\).

Answer:

\(\frac{\pi x}{2}-\frac{x^2}{2}+C\)

Question. 22

Evaluate the integral \(\int \frac{1}{\cos(x-a)\,\cos(x-b)}\,dx\).

Answer:

\(\frac{1}{\sin(a-b)}\log\left|\frac{\cos(x-a)}{\cos(x-b)}\right|+C\)

Question.  23

\(\int \frac{\sin^2 x-\cos^2 x}{\sin^2 x\cos^2 x}\,dx\) is equal to

(a)

\(\tan x+\cot x+C\)

(b)

\(\tan x+\cosec x+C\)

(c)

\(-\tan x+\cot x+C\)

(d)

\(\tan x+\sec x+C\)

Question.  24

\(\int \frac{e^x(1+x)}{\cos^2(e^x x)}\,dx\) equals

(a)

\(-\cot(e^x x)+C\)

(b)

\(\tan(xe^x)+C\)

(c)

\(\tan(e^x)+C\)

(d)

\(\cot(e^x)+C\)

NCERT Solutions Class 12 – Mathematics Part-2 – Chapter 7: INTEGRALS – Exercise 7.3 | Detailed Answers