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