Differentiation Question 264

Question: If $ y={{\tan }^{-1}}( \frac{\sqrt{a}-\sqrt{x}}{1+\sqrt{ax}} ) $ , then $ \frac{dy}{dx}= $

[AI CBSE 1988]

Options:

A) $ \frac{1}{2(1+x)\sqrt{x}} $

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

C) $ -\frac{1}{2(1+x)\sqrt{x}} $

D) None of these

Show Answer

Answer:

Correct Answer: C

Solution:

$ y={{\tan }^{-1}}\sqrt{a}-{{\tan }^{-1}}\sqrt{x} $

Differentiating w.r.t. x, we get, $ \frac{dy}{dx}=-\frac{1}{(1+x)}.\frac{1}{2\sqrt{x}} $ .