Differentiation Question 336

Question: $ \frac{d}{dx}{{\tan }^{-1}}\frac{x}{\sqrt{a^{2}-x^{2}}}= $

Options:

A) $ \frac{a}{a^{2}+x^{2}} $

B) $ \frac{-a}{a^{2}+x^{2}} $

C) $ \frac{1}{a\sqrt{a^{2}-x^{2}}} $

D) $ \frac{1}{\sqrt{a^{2}-x^{2}}} $

Show Answer

Answer:

Correct Answer: D

Solution:

$ \frac{d}{dx}{{\tan }^{-1}}\frac{x}{\sqrt{a^{2}-x^{2}}} $

Putting $ x=a\sin \theta , $ we get $ =\frac{d}{dx}[ {{\tan }^{-1}}\frac{a\sin \theta }{a\cos \theta } ]=\frac{d}{dx}[ {{\tan }^{-1}}\tan \theta ]=\frac{d}{dx}[\theta ] $

Substituting value of $ \theta $ , so $ |x| $ .