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Question Number 10469 by FilupSmith last updated on 11/Feb/17

One definition of Γ (x + 1) is :

Γ (x + 1) = \int_{0}^{\infty} e^{- t} t^{x} d x

According to WolframAlpha, another

definition is :

Γ (x + 1) = \frac{1}{e^{2 i π x} - 1} \oint_{L} e^{- t} t^{x} d x

Can someone explian to me where this

comes from and what it means .

Also, its been a long time since I learnt

contour integrals, so what does \oint_{L} mean ?