I'm in third year undergraduate physics, and more and more I'm seeing problems in homework and assignments that say "Prove that" and "Show that", basically just deriving equations. There's just one problem, I can't do it for the life of me. I had a thermodynamics test recently, and despite understanding the material and how all the equations work, I failed the test because the questions were proofs. I look at problems like this and all I see is a million different possible things to do with the equation, but none of them seem to lead me to the desired solution. Then when I see the solution afterwards, I realize how stupid I was and how simple the problem really is, which will probably be exactly what happens with the test I wrote. Studying also seems impossible as well, because even if I practice a proof, there's an entirely different kind that will be asked of me on a test. Is there any special way to get good at these derivations or am I just doomed to failure even though I understand the concepts?