For the first, you need to use the identities and . See what you can do after you've done that...
For the second, try working on the RHS. Start by multiplying top and bottom of the RHS by .
I have tried to sub in cos˛x+sin˛x=1 for 1 and then cancelling but that wouldnt work. I think you need to convert the sinx/cosx into tanx but im still not sure.
Another one i got stuck on. I tried to start with the LHS but wasnt sure whether to expand the brackets ot to turn sec into 1/cos and then turn the tan into sin/cos which would make a common denominator. However the ˛ is still there and I have no idea what to do with that haha
Any help would be appreciated, even just an idea for a start would be good