Start from the right side and write and in terms of and .
Hello there!
I have this problem on proving identities. I've been working on it for hours, but can't seem to get it right. The sad thing is that it's not even a double angle formula
cos x + sin x = [cos x / (1 - tan x)] + [sin x / (1 - cot x)]
Any help would be greatly appreciated. Thanks!