Hi there it would be greatly appreciated if someone could help me out with a few things to do with double angles and proving trig identities:

These are some of my hw questions:

tanx=csc2x-cot2x

1-sin2x=1-tanx

cos2x 1+tanx

sin4x-sin2x=cos3x

sin2x cosx

I seem to start theses problems okay but then i end up getting suck just because im unsure of what i can or cant do

Can someone please help with full solutions just so i can get a better understanding for tomorrow

Thanks