NCERT Solutions
Class 12 - Mathematics Part-2 - Chapter 7: INTEGRALS
Exercise 7.8

Question. 1

Evaluate \(\int_{-1}^{1} (x+1)\,dx\).

Answer:

2

Question. 2

Evaluate \(\int_{2}^{3} \frac{1}{x}\,dx\).

Answer:

\(\log\frac{3}{2}\)

Question. 3

Evaluate \(\int_{1}^{2} (4x^3-5x^2+6x+9)\,dx\).

Answer:

\(\frac{64}{3}\)

Question. 4

Evaluate \(\int_{0}^{\pi/4} \sin 2x\,dx\).

Answer:

\(\frac{1}{2}\)

Question. 5

Evaluate \(\int_{0}^{\pi/2} \cos 2x\,dx\).

Answer:

0

Question. 6

Evaluate \(\int_{4}^{5} e^x\,dx\).

Answer:

\(e^4(e-1)\)

Question. 7

Evaluate \(\int_{0}^{\pi/4} \tan x\,dx\).

Answer:

\(\frac{1}{2}\log 2\)

Question. 8

Evaluate \(\int_{\pi/6}^{\pi/4} \cosec x\,dx\).

Answer:

\(\log\left(\frac{\sqrt{2}-1}{2-\sqrt{3}}\right)\)

Question. 9

Evaluate \(\int_{0}^{1} \frac{dx}{\sqrt{1-x^2}}\).

Answer:

\(\frac{\pi}{2}\)

Question. 10

Evaluate \(\int_{0}^{1} \frac{dx}{1+x^2}\).

Answer:

\(\frac{\pi}{4}\)

Question. 11

Evaluate \(\int_{2}^{3} \frac{dx}{x^2-1}\).

Answer:

\(\frac{1}{2}\log\frac{3}{2}\)

Question. 12

Evaluate \(\int_{0}^{\pi/2} \cos^2 x\,dx\).

Answer:

\(\frac{\pi}{4}\)

Question. 13

Evaluate \(\int_{2}^{3} \frac{x\,dx}{x^2+1}\).

Answer:

\(\frac{1}{2}\log 2\)

Question. 14

Evaluate \(\int_{0}^{1} \frac{2x+3}{5x^2+1}\,dx\).

Answer:

\(\frac{1}{5}\log 6+\frac{3}{\sqrt{5}}\tan^{-1}\sqrt{5}\)

Question. 15

Evaluate \(\int_{0}^{1} x e^{x^2}\,dx\).

Answer:

\(\frac{1}{2}(e-1)\)

Question. 16

Evaluate \(\int_{1}^{2} \frac{5x^2}{x^2+4x+3}\,dx\).

Answer:

\(5-\frac{5}{2}\left(9\log\frac{5}{4}-\log\frac{3}{2}\right)\)

Question. 17

Evaluate \(\int_{0}^{\pi/4} (2\sec^2 x+x^3+2)\,dx\).

Answer:

\(\frac{\pi^4}{1024}+\frac{\pi}{2}+2\)

Question. 18

Evaluate \(\int_{0}^{\pi} \left(\sin^2\frac{x}{2}-\cos^2\frac{x}{2}\right)\,dx\).

Answer:

0

Question. 19

Evaluate \(\int_{0}^{2} \frac{6x+3}{x^2+4}\,dx\).

Answer:

\(3\log 2+\frac{3\pi}{8}\)

Question. 20

Evaluate \(\int_{0}^{1} \left(x e^x+\sin\frac{\pi x}{4}\right)\,dx\).

Answer:

\(1+\frac{4}{\pi}-\frac{2\sqrt{2}}{\pi}\)

Question.  21

\(\int_{1}^{\sqrt{3}} \frac{dx}{1+x^2}\) equals

(a)

\(\frac{\pi}{3}\)

(b)

\(\frac{2\pi}{3}\)

(c)

\(\frac{\pi}{6}\)

(d)

\(\frac{\pi}{12}\)

Question.  22

\(\int_{0}^{2/3} \frac{dx}{4+9x^2}\) equals

(a)

\(\frac{\pi}{6}\)

(b)

\(\frac{\pi}{12}\)

(c)

\(\frac{\pi}{24}\)

(d)

\(\frac{\pi}{4}\)

NCERT Solutions Class 12 – Mathematics Part-2 – Chapter 7: INTEGRALS – Exercise 7.8 | Detailed Answers