Inverse Trigonometric Functions Question 135
Question: If $ \pi \le x\le 2\pi $ , then $ {{\cos }^{-1}}(\cos x) $ is equal to
Options:
A) $ x $
B) $ -x $
C) $ 2\pi +x $
D) $ 2\pi -x $
Show Answer
Answer:
Correct Answer: D
Solution:
It is given that $ \pi \le x\le 2\pi $
$ \Rightarrow -\pi \ge -x\ge -2\pi \Rightarrow \pi \ge 2\pi -x\ge 0 $
$ \Rightarrow {{\cos }^{-1}}{ \cos (2\pi -x) }=2\pi -x $ .
BETA
