Answer
$\frac{\sin^{2}\theta}{\cos\theta} $
Work Step by Step
Given expression is-
$ \frac{1}{\cos\theta} - \cos\theta $
= $ \frac{1}{\cos\theta} - \cos\theta\times\frac{\cos\theta}{\cos\theta} $
= $ \frac{1}{\cos\theta} -\frac{\cos^{2}\theta}{\cos\theta} $
= $ \frac{1 - \cos^{2}\theta}{\cos\theta} $
= $\frac{\sin^{2}\theta}{\cos\theta} $
