I am trying to prove that
If polynomial order of is 2 or more than that of , using the theorem stating that if a function has a finite number of singular points all interior to a contour , then
I received the hint that, under the conditions described above, the rational function in the integrand can be written as a McLauran Series with no negative powers of z. This would imply that the residue is zero...
My problem is, I can't seem to wrap my head around how the rational function given to me can be written into the form of a power series with only positive exponents...
So, as the title says, When can a rational function be represented as a power series? I'm not looking for a full proof, but a few details would be nice, just so I feel more comfortable running with the hint.