Here's another one for you folks:

I have no idea which trigonometric identity to use... could you guys give me an idea.

I feel like the only one might possibly be [tex] sin(x)cos(y) = 1/2(sin(x+y) + sin(x-y)) but I don't feel like this is the right one.

Please tell me I'm not just over thinking it... could you do this? I'm also 100% sure you couldn't do this but just making sure.

equals ?