Answer
$\frac{\cos^{2}\theta}{\sin\theta} $
or
$\cot\theta\cos\theta$
Work Step by Step
Given expression is-
$ \frac{1}{\sin\theta} - \sin\theta $
= $ \frac{1}{\sin\theta} - \sin\theta\times\frac{\sin\theta}{\sin\theta} $
= $ \frac{1}{\sin\theta} -\frac{\sin^{2}\theta}{\sin\theta} $
= $ \frac{1 - \sin^{2}\theta}{\sin\theta} $
= $\frac{\cos^{2}\theta}{\sin\theta} $
(Recall first Pythagorean identity)
= $\frac{\cos\theta}{\sin\theta}. \cos\theta $
=$\cot\theta\cos\theta$
