# Homework Help: Confusion with formulas for wavefunctions

1. Apr 1, 2017

### Cocoleia

1. The problem statement, all variables and given/known data
I am working on this problem:

The formula I am given in my notes is:

I found a website which explains this problem, and they give this formula:

And I don't see how they went from sqrt(8) to 2 on the numerator. I am confused which formula to use where.
I am confused as to which formula I should use... my notes don't make any difference between L1, L2 and L3, but then it doesn't matter in this case in the end.

2. Apr 1, 2017

### PeroK

You have found a solution for the 3D problem. Yours is the 2D problem, which is slightly different.

3. Apr 1, 2017

### Cocoleia

The solution I found was supposed to be for the exact same problem I am working on. In this case do I use the formula from my notes ? Or there is a completely different one that I am forgetting ?

4. Apr 1, 2017

### Cocoleia

Could I use this one:

and then add the y-component somehow ?

5. Apr 1, 2017

### PeroK

You've found the 1D solution and the 3D solution. I think you are supposed to solve the 2D problem for yourself!

6. Apr 1, 2017

### eys_physics

Yes, your problem in 2- or 3 dimension is separable. That, is the wave function for the 2-dimensional problem can be written as a product of two wave functions, one depending on $x$ and the other on $y$.