Residue

#Math

$\displaystyle \text{Res}{z=z{0}}f=a_{-1}:f(z)=\sum_{k = -\infty}^{\infty}a_{k}(z-z_{0})^{k}$

• The residue of $\displaystyle f$ at a singularity (Math) $\displaystyle z_{0}$ is the coefficient $\displaystyle a_{-1}$ for the Laurent Series power series expansion of a function