residue [r, p, k, e] = residue (b, a) [b, a] = residue (r, p, k) [b, a] = residue (r, p, k, e) b: Real or complex valued vector or matrix a: Real or complex valued vector or matrix The first calling form computes the partial fraction expansion for the quotient of the polynomials, b and a. This function works for transfer functions which are proper fractions. NOTE that the polynomials 'b' and 'a' should have real coefficients(because of the function 'filter' used in polyval) The second and the third calling forms perform the inverse operation of the first calling form. \begin{eqnarray} \frac{B(s)}{A(s)}=\sum_{m=1}^{M}\frac{r(m)}{(s-p(m))^{e(m)}}+\sum_{i=1}^{N}k(i)*{s^{N-i}} \end{eqnarray}