Question

The range of the function $y={\left(\frac{{\cos }^{-1}(3x-1)}{\pi }+1\right)}^2$ is

• A. $[1,4]$
• B. $[0,\pi ]$
• C. $[1,\pi ]$
• D. $\left[0,{\pi }^2\right]$

Answer 1

Answer: (A)

$-1\le 3x-1\le 1\Rightarrow 0\le x\le \frac{2}{3}\Rightarrow$ domain is $\left[0,\frac{2}{3}\right]$
when $x=0$ then $y=1;x=\frac{2}{3},y=4$. Hence range is $[1,4]$