
gamma - Gamma function

Calling sequence:
gamma(x)

Parameter:

x  --   expression

Summary:

The Gamma function is defined as

    gamma(x) = int( exp(-t) * t^(x-1), t=0..infinity )

If the argument x is a non-negative integer then is gamma(x) = fact(x-1).
The Gamma function can be seen as a generalization of the factorial function.
The Gamma function is also defined for complex arguments. gamma returns
the function call with evaluated arguments, if the argument cannot be evaluated
to a number. gamma is a kernel function.

>>  gamma(3.4);

     2.981206426

>>  gamma(23);

      1124000727777607680000

>>  gamma(I); float(%);

      gamma(I)

      - 0.1549498283 - 0.4980156681 I

See also:  igamma , fact

