Particle in a box with non-flat bottom

[bon]

Homework Statement

please see q attached..

Homework Equations

The Attempt at a Solution

Ok so I've shown that all the first order energy shifts are zero. I'm just not sure what the simple explanation for this is...?


THanks!

 

[bon]

also - another question says: discuss the constrains on W for perturbation theory to be asuitable approx method.

What can i say beyond W must be small? anything else..?

Thanks