Differentiation Question 163

Question: The differential coefficient of $ {{\tan }^{-1}}\sqrt{x} $ with respect to $ \sqrt{x} $ is

[MP PET 1987]

Options:

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

B) $ \frac{1}{2x\sqrt{1+x}} $

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

D) $ \frac{1}{1+x} $

Show Answer

Answer:

Correct Answer: D

Solution:

Let $ y_1={{\tan }^{-1}}\sqrt{x} $ and $ y_2=\sqrt{x} $

Differentiating w.r.t. x of $ y_1 $ and $ y_2 $ , we get $ \frac{dy_1}{dx}=\frac{1}{(1+x)}.\frac{1}{2\sqrt{x}} $ and $ \frac{dy_2}{dx}=\frac{1}{2\sqrt{x}} $

Hence $ \frac{dy_1}{dy_2}=\frac{1}{1+x} $ .