Solve each trig identity.

a) sec2(x) = [sec^2(x)]/[2 - sec^2(x)]

b) sec2(x) = [1 + tan^2(x)]/[1 - tan^2(x)]

c) [cot(x) - tan(x)]/[cot(x) + tan(x)] = cos2(x)

I did the ones using sin and cos

for these try using
sec^2(x) = 1 + tan^2(x)
or convert everything to sin(x) and cos(x) first