Inverse Trigonometric Functions Question 124

Question: If $ \frac{\pi }{2}\le x\le \frac{3\pi }{2}, $ then $ {{\sin }^{-1}}(\sin x) $ is equal to

Options:

A) $ x $

B) $ -x $

C) $ \pi +x $

D) $ \pi -x $

Show Answer

Answer:

Correct Answer: D

Solution:

We have $ \frac{\pi }{2}\le x\le \frac{3\pi }{2} $

$ \Rightarrow \frac{-\pi }{2}\le x-\pi \le \frac{\pi }{2}\Rightarrow \frac{-\pi }{2}\le \pi -x\le \frac{\pi }{2} $

$ \Rightarrow {{\sin }^{-1}}{\sin (\pi -x)}=\pi -x $ .