Consider the following expressions as right hand sides of identities. Find a suitable left hand side from (A-C) that completes each identity.

 1. $\tan(x)\cos(x)+\csc(x)\sin^2(x)$
 2. $\displaystyle{\frac{4\sec^2(x)+4\sec(x)+1}{2\sec(x)+1}}$
 3. $\cot(x)\sin(x)-\cos^2(x)\sec(x)$

Answers:

A. $0$
B. $\displaystyle{\frac{2}{\cos(x)}+1}$
C. $2\sin(x)$