Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section A

Chapter

Indefinite Integration

Question:

If $I=\int \frac{e^{\tan ^{-1}} x}{\left(1+x^2\right)}\left\{\left(\sec ^{-1} \sqrt{1+x^2}\right)^2+\cos ^{-1}\left(\frac{1-x^2}{1+x^2}\right)\right\} d x$. Then,

Options:

$I=e^{\tan ^{-1} x}\left(\tan ^{-1} x\right)+C$

$I=e^{\tan ^{-1} x}\left(\sec ^{-1} \sqrt{1+x^2}\right)^2+C$

$I=\frac{1}{2} e^{\tan ^{-1} x}\left(\tan ^{-1} x\right)^2+C$

$I=e^{\tan ^{-1} x}\left(cosec^{-1} \sqrt{1+x^2}\right)^2+C$

Correct Answer:

$I=e^{\tan ^{-1} x}\left(\sec ^{-1} \sqrt{1+x^2}\right)^2+C$

Explanation:

Let $\tan ^{-1} x=\theta$ or $x=\tan \theta$. Then,

$I=\int e^\theta\left(\theta^2+2 \theta\right) d \theta=e^\theta \theta^2+C$

$\Rightarrow I=e^{\tan ^{-1} x}\left(\tan ^{-1} x\right)^2+C$

$\Rightarrow I=e^{\tan ^{-1} x}\left(\sec ^{-1} \sqrt{1+x^2}\right)^2+C$