NCERT Solutions
Class 12 - Mathematics Part-2 - Chapter 7: INTEGRALS
Exercise 7.1

Question. 1

Find an anti derivative (or integral) of \(\sin 2x\) by the method of inspection.

Answer:

\(-\frac{1}{2}\cos 2x\)

Question. 2

Find an anti derivative (or integral) of \(\cos 3x\) by the method of inspection.

Answer:

\(\frac{1}{3}\sin 3x\)

Question. 3

Find an anti derivative (or integral) of \(e^{2x}\) by the method of inspection.

Answer:

\(\frac{1}{2}e^{2x}\)

Question. 4

Find an anti derivative (or integral) of \((ax + b)^2\) by the method of inspection.

Answer:

\(\frac{1}{3a}(ax + b)^3\)

Question. 5

Find an anti derivative (or integral) of \(\sin 2x - 4e^{3x}\) by the method of inspection.

Answer:

\(-\frac{1}{2}\cos 2x - \frac{4}{3}e^{3x}\)

Question. 6

Evaluate the integral \(\int (4e^{3x} + 1)\,dx\).

Answer:

\(\frac{4}{3}e^{3x} + x + C\)

Question. 7

Evaluate the integral \(\int x^2\left(1 - \frac{1}{x^2}\right)dx\).

Answer:

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

Question. 8

Evaluate the integral \(\int (ax^2 + bx + c)\,dx\).

Answer:

\(\frac{ax^3}{3} + \frac{bx^2}{2} + cx + C\)

Question. 9

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

Answer:

\(\frac{2}{3}x^3 + e^x + C\)

Question. 10

Evaluate the integral \(\int \left(\sqrt{x} - \frac{1}{\sqrt{x}}\right)^2 dx\).

Answer:

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

Question. 11

Evaluate the integral \(\int \frac{x^3 + 5x^2 - 4}{x^2} dx\).

Answer:

\(\frac{x^2}{2} + 5x + \frac{4}{x} + C\)

Question. 12

Evaluate the integral \(\int \frac{x^3 + 3x + 4}{\sqrt{x}} dx\).

Answer:

\(\frac{2}{7}x^{7/2} + 2x^{3/2} + 8\sqrt{x} + C\)

Question. 13

Evaluate the integral \(\int \frac{x^3 - x^2 + x - 1}{x - 1} dx\).

Answer:

\(\frac{x^3}{3} + x + C\)

Question. 14

Evaluate the integral \(\int (1 - x)\sqrt{x}\,dx\).

Answer:

\(\frac{2}{3}x^{3/2} - \frac{2}{5}x^{5/2} + C\)

Question. 15

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

Answer:

\(\frac{6}{7}x^{7/2} + \frac{4}{5}x^{5/2} + 2x^{3/2} + C\)

Question. 16

Evaluate the integral \(\int (2x - 3\cos x + e^x)\,dx\).

Answer:

\(x^2 - 3\sin x + e^x + C\)

Question. 17

Evaluate the integral \(\int (2x^2 - 3\sin x + 5\sqrt{x})\,dx\).

Answer:

\(\frac{2}{3}x^3 + 3\cos x + \frac{10}{3}x^{3/2} + C\)

Question. 18

Evaluate the integral \(\int \sec x(\sec x + \tan x)\,dx\).

Answer:

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

Question. 19

Evaluate the integral \(\int \frac{\sec^2 x}{\cosec^2 x}\,dx\).

Answer:

\(\tan x - x + C\)

Question. 20

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

Answer:

\(2\tan x - 3\sec x + C\)

Question.  21

The anti derivative of \(\left(\sqrt{x} + \frac{1}{\sqrt{x}}\right)\) equals

(a)

\(\frac{1}{3}x^{1/3} + 2x^{1/2} + C\)

(b)

\(\frac{2}{3}x^{2/3} + \frac{1}{2}x^2 + C\)

(c)

\(\frac{2}{3}x^{3/2} + 2x^{1/2} + C\)

(d)

\(\frac{3}{2}x^{3/2} + \frac{1}{2}x^{1/2} + C\)

Question.  22

If \(\frac{d}{dx}f(x) = 4x^3 - \frac{3}{x^4}\) such that \(f(2) = 0\), then \(f(x)\) is

(a)

\(x^4 + \frac{1}{x^3} - \frac{129}{8}\)

(b)

\(x^3 + \frac{1}{x^4} + \frac{129}{8}\)

(c)

\(x^4 + \frac{1}{x^3} + \frac{129}{8}\)

(d)

\(x^3 + \frac{1}{x^4} - \frac{129}{8}\)

NCERT Solutions Class 12 – Mathematics Part-2 – Chapter 7: INTEGRALS – Exercise 7.1 | Detailed Answers