Can you please solve these 3 trig proofs for me.

sec=sin(cot+tan)

(sec)(cot)-cot=tan

sin^2-sin^4=cos^2-cos^4

In each case start by changing the cotangent secant, and tangent functions to their sine and cosine equivalents. Then it's simply a matter of manipulating the terms, and applying the well-known identity sin^2x + cos^2x = 1. One correction though - the second identity is written incorrectly, it should be: (sec^2x) (cot x) - cot x = tan x.