In both cases you should start by using the compound angle formulae:

sin(A - B) = sin A cos B - sin B cos A

cos(A - B) = cos A cos B + sin A sin B

sin(A + B) = sin A cos B + sin B cos A

I'm assuming there's something missing on the right hand side of the first one .......

For the second one it also helps to know that .

Where are you stuck?