There are a few nice "recipes" for calculating Residues

  1. Let f:C{0}C be given by f(z)=ez1z10. Then Resz=0f(z)=19!
  2. Let f:UC be holomorphic, and z0 a pole of degree m. Suppose there exists ϕ:Br(z0)C holomorphic such that on Br(z0){z0}, we have that f(z)=ϕ(z)(zz0)m. Then we have that resz=z0(f(z))=ϕ(m1)(z0)(m1)!
  3. Suppose f:UC is holomorphic, and f(z)=1g(z) for z0 asimple zero of g (g is also holomorphic). Then we have that Resz=z0f(z)=1g(z0).
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