Question
The range of the function, $\text{f(x)}=(1+\sec^{-1}\text{x})(1+\cos^{-1}\text{x})$ is:
- $(-\infty,\infty)$
- $(-\infty,0]\cup[4.\infty)$
- $\big\{0,(1+\pi^2)\big\}$
- $[1.(1+\pi)^2]$