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Residue Formula

Source lecture(s): PHY622 Lec4

Physical Meaning

Evaluates closed contours by summing local pole strengths.

Variable Definitions

Symbol Meaning
\(\text{Res}\) residue at pole
\(z_k\) pole locations

Assumptions

Isolated singularities inside contour.

Derivation

Deform to small circles around poles; each contributes \(2\pi i\cdot\text{Res}\).

Applications

Evaluating real integrals, summing series, inverse Laplace transforms.

Connections to Other Equations

  • cauchy-theorem
  • cauchy-integral-formula