Inverse Trigonometric Functions Question 154

Question: $ \tan [ {{\sec }^{-1}}\sqrt{1+x^{2}} ]= $

Options:

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

B) x

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

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

Show Answer

Answer:

Correct Answer: B

Solution:

$ \tan ( {{\sec }^{-1}}\sqrt{1+x^{2}} )=\tan ( {{\sec }^{-1}}\sqrt{1+{{\tan }^{2}}\theta } ) $ (Putting $ x=\tan \theta ) $

$ =\tan ({{\sec }^{-1}}\sec \theta )=\tan \theta =x $ .