Hello, I have a quantum mechanics problem. Here is the problem statement. I must derive this formula, L+-L- =-(h/2π)^2[d²/dθ²+cotθ d/dθ +cot²θ d²/dθ²+id/dφ] from this formula, L+-L-=±(h/2π)e^±(iθ)[d/dθ + i cotθ d/dφ] I have no idea how to approach this problem. Can anyone give me a suggestion on how to begin the proof? Thanks.