12.1.1 Factorials
The factorial
or its postfix operator equivalent
!
command computes the factorial of a number.
-
factorial takes
n, an integer.
- factorial(n) returns n!.
- The Γ function (see Section 7.3.13) is used to extend
the factorial function to complex numbers. The Γ function is
defined for all complex numbers except for zero and the negative
integers, and it satisfies Γ(n+1)=n! for all non-negative
integers n. So the factorial can be extended to all complex numbers
except the negative integers by n!=Γ(n+1).
Examples
or: