Answer
$ = \sqrt{5}$
Work Step by Step
$\sec (\cos ^ {–1} \frac{1}{\sqrt{5}})$
let, $\cos ^ {–1} \frac{1}{\sqrt{5}} = \theta$
then, $\cos \theta = \frac{1}{\sqrt{5}}$
We know, $\sec \theta = \frac{1}{\cos \theta}$
$\sec \theta = \frac{1}{\frac{1}{\sqrt{5}}}$
$ = \sqrt{5}$
