Answer
See explanations.
Work Step by Step
$LHS=\frac{sin^2\theta-sin\theta/cos\theta}{cos^2\theta-cos\theta/sin\theta}\times\frac{sin\theta cos\theta}{sin\theta cos\theta}=\frac{sin^2\theta(sin\theta cos\theta-1)}{cos^2\theta(sin\theta cos\theta-1)}=tan^2\theta=RHS$
