Residue of a repeated pole.
RESI2(U,V,POLE,N,K) returns the residue of a repeated pole
of order N and the K-th power denominator of [1 -pole], where
U and V represent the original polynomial ratio U/V.
For example, if P is a pole of multiplicity 2,
then this routine should be called twice with N = 2,
first using K = 1, then K = 2. If K is not provided,
it defaults to N. If N is not provided, it defaults to 1.
See also RESIDUE , POLYDER