Find the residues of at all its isolated singular points and at infinity (if infinity is not a limit point of singular points), where is given by
This has poles at of multiplicity and at of multiplicity .
For the simple roots, the residue is the numerator divided by the first derivative of the denominator when both are evaluated at the root.
For 0, use the formula
If is analytic except at isolated singular points, then the sum of all the residues of equals 0.