Differentiation Question 250

Question: The derivative of $ {{\sin }^{-1}}( \frac{2x}{1+x^{2}} ) $ w.r.t. $ {{\cos }^{-1}}( \frac{1-x^{2}}{1+x^{2}} ) $ is

[Karnataka CET 2000; Pb. CET 2004]

Options:

A) -1

B) 1

C) 2

D) 4

Show Answer

Answer:

Correct Answer: B

Solution:

Let $ p={{\sin }^{-1}}\frac{2x}{1+x^{2}}=2{{\tan }^{-1}}x $

and $ q={{\cos }^{-1}}\frac{1-x^{2}}{1+x^{2}}=2{{\tan }^{-1}}x $ ; \ $ \frac{dp}{dq}=\frac{dp/dx}{dq/dx}=1 $ .