1. The problem statement, all variables and given/known data 2. Relevant equations 3. The attempt at a solution The issue I'm having here is that the problem should be able to be done rather quickly. I can see how to solve for <H> using the operator, but there's a quick way that I'm not picking up on. I thought about solving <H> = <p^2> / 2m, but getting <p^2> is just as much of a pain. Any help ?