Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Indefinite Integration

Question:

Find an anti-derivative of the function $\frac{1}{x}, x \neq 0$ using the method of inspection.

Options:

$x^{-2}$

$e^x$

$\log |x|$

$\frac{x^2}{2}$$

Correct Answer:

$\log |x|$

Explanation:

The correct answer is Option (3) → $\log |x|$

We know that

$\frac{d}{dx} (\log x) = \frac{1}{x}, x > 0 \text{ and } \frac{d}{dx} [\log (-x)] = \frac{1}{-x} (-1) = \frac{1}{x}, x < 0$

Combining above, we get $\frac{d}{dx} (\log |x|) = \frac{1}{x}, x \neq 0$

Therefore, $\int \frac{1}{x} \, dx = \log |x|$ is one of the anti derivatives of $\frac{1}{x}$.