If $y=\left(x+\sqrt{x^2+1}\right)^m$, then $\frac{dy}{dx}$ is
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → $\frac{my}{\sqrt{x^2+1}}$
Given:
$y = \left(x + \sqrt{x^2 + 1} \right)^m$
Step 1: Let
$u = x + \sqrt{x^2 + 1}$
Then, $y = u^m$
Step 2: Differentiate using the chain rule:
$\frac{dy}{dx} = m u^{m-1} \cdot \frac{du}{dx}$
Step 3: Compute $\frac{du}{dx}$
$\frac{du}{dx} = \frac{d}{dx}\left(x + \sqrt{x^2 + 1}\right) = 1 + \frac{1}{2\sqrt{x^2 + 1}} \cdot 2x = 1 + \frac{x}{\sqrt{x^2 + 1}}$
Step 4: Final Answer
$\frac{dy}{dx} = m \left(x + \sqrt{x^2 + 1} \right)^{m-1} \left(1 + \frac{x}{\sqrt{x^2 + 1}} \right)$