Answer
$\sin ^{2}\alpha sec^2\alpha +\sin ^{2}\alpha csc^2\alpha =sec^2\alpha $
Work Step by Step
$\sin ^{2}\alpha sec^2\alpha +\sin ^{2}\alpha csc^2\alpha =\sin ^{2}\alpha \left( \dfrac {1}{\cos ^{2}\alpha }+\dfrac {1}{\sin ^{2}\alpha }\right) =\dfrac {\sin ^{2}\alpha }{\cos ^{2}\alpha \sin ^{2}\alpha }\left( \cos ^{2}\alpha +\sin ^{2}\alpha \right) =\dfrac {1}{\cos ^{2}\alpha }=sec^2\alpha $
