This is documentation for Mathematica 8, which was
based on an earlier version of the Wolfram Language.

# Gamma

 Gamma[z]is the Euler gamma function . Gammais the incomplete gamma function . Gammais the generalized incomplete gamma function .
• Mathematical function, suitable for both symbolic and numerical manipulation.
• The gamma function satisfies .
• The incomplete gamma function satisfies .
• The generalized incomplete gamma function is given by the integral .
• Note that the arguments in the incomplete form of Gamma are arranged differently from those in the incomplete form of Beta.
• Gamma[z] has no branch cut discontinuities.
• Gamma has a branch cut discontinuity in the complex z plane running from to .
• For certain special arguments, Gamma automatically evaluates to exact values.
• Gamma can be evaluated to arbitrary numerical precision.
• Gamma automatically threads over lists.
Integer values:
Half-integer values:
Evaluate numerically for complex arguments:
Integer values:
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Half-integer values:
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Evaluate numerically for complex arguments:
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 Scope   (5)
Evaluate for large arguments:
Evaluate to high precision:
The precision of the output tracks the precision of the input:
Series expansion:
Incomplete gamma function:
Infinite arguments give symbolic results:
Gamma can be applied to a power series:
Series expansion at poles:
Expansion at symbolically specified negative integers:
Series expansion at infinity (Stirling approximation):
Give the result for an arbitrary symbolic direction:
Evaluate symbolically at integer and half-integer orders:
Series expansion at a generic point:
Series expansion at infinity:
Evaluate symbolically at integer and half-integer orders:
Series expansion at a generic point:
 Applications   (5)
Plot of the absolute value of Gamma in the complex plane:
Find the asymptotic expansion of ratios of gamma functions:
Volume of an -dimensional unit hypersphere:
Low-dimensional cases:
Plot the volume of the unit hypersphere as a function of dimension:
Plot the real part of the incomplete gamma function over the parameter plane:
CDF of the -distribution:
Calculate the PDF:
Plot the CDF for different numbers of degrees of freedom:
Use FullSimplify to simplify gamma functions:
Numerically find a root of a transcendental equation:
Sum expressions involving Gamma:
Generate from integrals, products, and limits:
Obtain Gamma as the solution of a differential equation:
Integrals:
Large arguments can give results too large to be computed explicitly:
Machine-number inputs can give high-precision results:
Nest Gamma over the complex plane:
Fractal from iterating Gamma:
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