Question

${\cos }^{-1}(\cos x)=x$ is satisfied by

• A. $x\in R$
• B. $x\in [0,\pi ]$
• C. $x\in [-1,1]$
• D. none of these

Answer 1

Answer: (B)

$co{s}^{-1}\left(cosx\right)=x$
if $0\le x\le \pi$ i.e.,
if $x\in \left[0,\pi \right]$