Inverse Trigonometric Functions Question 73

Question: The range of $ f(x)=si{n^{-1}}x+{{\tan }^{-1}}x+{{\sec }^{-1}}x $ is

Options:

A) $ ( \frac{\pi }{4},\frac{3\pi }{4} ) $

B) $ [ \frac{\pi }{4},\frac{3\pi }{4} ] $

C) $ { \frac{\pi }{4},\frac{3\pi }{4} } $

D) None of these

Show Answer

Answer:

Correct Answer: C

$ f(x)=si{n^{-1}}x+{{\tan }^{-1}}x+{{\sec }^{-1}}x; $

clearly, the domain of $ f(x) $ is $ x=\pm 1. $

Thus the range is $ {f(1),f(-1)},i.e.,{ \frac{\pi }{4},\frac{3\pi }{4} }. $