A particle of mass m is confined to move in a one-dimensional "infinite" potential well defined by V(x)=0, |x|< or=a, V(x)=infinity otherwise. The energy eigenvalues are E(subscript n)=((n^2)(pi^2)(h-bar^2))/(8m a^2), with n=1,2,3,... and the orthonormal eigenfunctions are the even and odd functions
psi(subscript n)=
[1/(sqrt a)]cos(n pi x/2a) for n=1, 3, 5...
[1/(sqrt a)]sin(n pi x/2a) for n=2, 4, 6 ...
The potential is modified between -a
a) Determine the ground state energy to first-order in epsilon. (Note 2 sin Acos B=sin(A+B)+sin(A-B))