Question

The domain of the function $co{s}^{-1}(2x-1)$ is

• A. $[0,1]$
• B. $[-1,1]$
• C. $(-1,1)$
• D. $[0,\pi ]$

Answer 1

Answer: (A)

We have, $0\le co{s}^{-1}\left(2x-1\right)\le \pi$
$\Rightarrow -1\le 2x-1\le 1$
$\Rightarrow 0\le 2x\le 2$
$\Rightarrow 0\le x\le 1$
$\therefore$ Domain of $co{s}^{-1}\left(2x-1\right)=\left[0,1\right]$