1. The problem statement, all variables and given/known data "Prove that any two different nondegenerate bound eigenfunctions [itex]\psi[/itex]j(x) and [itex]\psi[/itex]i(x) that are solutions to the time-independent Schroedinger equation for the same potential V(x) obey the orthogonality relation [itex]\int[/itex]-∞∞ [itex]\psi [/itex]j*[itex]\psi[/itex]i(x)dx=0 " 2. Relevant equations I believe I have to find equations for which both eigenfunctions are solutions? 3. The attempt at a solution I'm lost on how to get the problem started. I cannot think of any eigenfunctions to use. I might be putting more thought to it than I need to though.