Recent content by haselwhat?

Yes, scattering. But I guess I'd like to read something about the classical theory first.

Does anybody know of any good references that explain the concepts/mathematics behind cross sections particularly well? Websites, textbooks, whatever...

Its just a trig identity I used once to show orthogonality. Hopefully it makes the integration easier and hopefully gives zero, which is your "RHS", right?

Remember omega is a continuous variable so considering its different values is more of a Fourier Series type of thinking... just integrate the way it is.

Try defining the indices like: 2n-1 = k and 2m-1 = j or something. (k=1,3,5,... and j=1,3,5,...). Then try making use of the trig identity sin(jx)sin(kx) = (1/2)[ cos((j-k)x) - cos((j+k)x) ] in the integrand.