Differentiation Question 242

Question: The derivative of $ \sqrt{\sqrt{x}+1} $ is

[SCRA 1996]

Options:

A) $ \frac{1}{\sqrt{x}(\sqrt{x}+1)} $

B) $ \frac{1}{\sqrt{x}\sqrt{x+1}} $

C) $ \frac{4}{\sqrt{x(\sqrt{x}+1)}} $

D) $ \frac{1}{4\sqrt{x(\sqrt{x}+1)}} $

Show Answer

Answer:

Correct Answer: D

Solution:

$ y=\sqrt{\sqrt{x}+1} $

$ \frac{dy}{dx}=\frac{1}{2\sqrt{\sqrt{x}+1}}\frac{d}{dx}(\sqrt{x}+1) $

$ \frac{dy}{dx}=\frac{1}{4\sqrt{x}.\sqrt{\sqrt{x}+1}}=\frac{1}{4\sqrt{x(\sqrt{x}+1)}} $ .