Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Indefinite Integration

Question:

Find $\int e^x \left(\tan^{-1} x + \frac{1}{1+x^2}\right) dx$

Options:

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

$e^x \tan^{-1} x + C$

$\frac{e^x}{1+x^2} + \tan^{-1} x + C$

$e^x (\tan^{-1} x)^2 + C$

Correct Answer:

$e^x \tan^{-1} x + C$

Explanation:

The correct answer is Option (2) → $e^x \tan^{-1} x + C$

We have $I = \int e^x \left(\tan^{-1} x + \frac{1}{1+x^2}\right) dx$

Consider $f(x) = \tan^{-1} x$, then $f'(x) = \frac{1}{1+x^2}$.

Thus, the given integrand is of the form $e^x [f(x) + f'(x)]$.

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