1. The problem statement, all variables and given/known data The question says to solve the Schrodinger equation for a particle in a box with periodic conditions and then it gives. ψ(0)=ψ(a) 3. The attempt at a solution I used the above BC and I also did it as its derivative. (It wasn't stated but I assumed it was implied. I had no other way to solve for anything.) Here is my work.. http://imageshack.us/a/img853/9774/qmproblem2.jpg [Broken] I was able to get the Energies, but I now have nothing left to solve for A and B! I was thinking of setting ψ(0)=0 or ψ(a)=0 but I don't know if this is correct because it is the same as the non-periodic condition.