# Proving time independence of energy eigenstates

1. Dec 1, 2009

### Gnator

1. The problem statement, all variables and given/known data
We are ask to find the probability density of psi(x,t). I know that psi have an exp term but i don't understand how by squaring psi make the exp term disappear.

2. Relevant equations
Psi = sqrt(2/L)sin(n*pi*x / L)e^(-2*pi* i(E/h)t

3. The attempt at a solution
I attempted changing the exp term into polar coord but I cant seem to get anywhere with that.

2. Dec 1, 2009

### Dick

You don't square psi. You multiply it by it's complex conjugate. Makes all the difference.

3. Dec 1, 2009

### Gnator

Yes, I just read my text and I discover you are suppose to multiple the complex conjugate. Thank you.