How to prove that Γ(z+1)=zΓ(z)?

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SUMMARY

The Gamma function satisfies the property Γ(z+1) = zΓ(z), which can be proven using integration by parts. The integral representation of the Gamma function is given by Γ(z) = ∫₀^∞ t^(z-1) e^(-t) dt. By setting u = e^(-t) and dv = t^(z-1) dt, and applying the integration by parts formula, the proof simplifies to showing that the remaining integral leads to the desired relationship. The application of L'Hôpital's Rule helps resolve the bounds, confirming the result.

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Homework Statement



I'm not sure how to prove that the Gamma function (the extension of the factorial) has the property that Γ(z+1) = zΓ(z).

Homework Equations



Γ(z)=\int_0^\infty t^{z-1} e^{-t}\,{\rm d}t

The Attempt at a Solution



Looking online, I should try integration by parts, but I'm still unsure as to how to attack the problem.
 
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Integrate the integrand in the expression for \Gamma(z) using integration by parts (\int udv = uv - \int vdu). Use u = e^{-t} and dv = t^{z-1}. Remember that t is the variable of integration and z is a constant.

After getting the expression, apply the bounds. The uv term is bounded by zero and infinity, and the upper bound can be resolved with L' Hopital's Rule (the limit is zero). The lower bound is also zero, so this term vanishes. You're left with an expression for the \int vdu term that's equivalent to \frac{1}{z}\Gamma(z+1). Now just do the simple algebra to finish off the proof.

EDIT: Can't believe I used zeta in place of gamma!
 
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