Calculate Eigen Function of 3D Potential Box w/ Doubled X Side

[SANKET HAQUE]

Suppose we have a 3D potential box having different length. Now suddenly we double the length of a particular side(Say along X direction) of the box. Can we calculate what will be the eigen function of the Hamiltonian. Is there Time Independent S.E. holds?

 

[WannabeNewton]

Yes you can do that but this sounds an awful lot like extremely standard QM HW problems so is this meant to be such?