Can someone help me prove the following identities:

(1+cos^2x/1+tan^2x) tanx=cotx

e) secx-cosx=sinxtanx f)sinxcosx/sinx=1+tanx\tanx g)cosx/sinx-sinx/secx=cos^2xcotx

h)cotx-tanx/cotx+tanx=2cos^2x-1 i)3sin^2x+4cos2x=3+cos^2x j)9sec^2x-5tan^2x=5+4sec^2x

k) (2cos^2x-1)^2/sin^4x-cos^4x=2sin^2x-1 L)(sin^2x/1-cosx)-1=cosx

m)1+cos2x/sin2x=cotx

Okay, here are these ones for now... the rest are not the same so I want to have these down first:) Thank you so much for helping by the way! I wish I was a math wizz too!