Question:
Prove the following identities (1-16)
$\frac{2 \sin x \cos x-\cos x}{1-\sin x+\sin ^{2} x-\cos ^{2} x}=\cot x$
Solution:
$\mathrm{LHS}=\frac{2 \sin x \cos x-\cos x}{1-\sin x+\sin ^{2} x-\cos ^{2} x}$
$=\frac{\cos x(2 \sin x-1)}{2 \sin ^{2} x-\sin x} \quad\left(\because 1-\cos ^{2} x=\sin ^{2} x\right)$
$=\frac{\cos x(2 \sin x-1)}{\sin x(2 \sin x-1)}$
$=\cot x$
= RHS
Hence proved.