Factorial()

Factorial()

Category: Number

Syntax: Factorial (number { ; numberOfFactors })

Parameters: number ”any expression that resolves to a positive integer; numberOfFactors ”any expression that resolves to a positive integer that represents how many factors to include in the multiplication.

Parameters in curly braces {} are optional.

Description: Returns the factorial of number , stopping either at 1 or stopping at the optional numberOfFactors . The factorial of a number n is defined as n x( n “1)x( n “2)x( n “3) x1. Factorials are useful in statistics and combinatorics. In mathematics, factorials are usually represented by an exclamation mark. 4! = Factorial (4) = 4 x 3 x 2 x 1 = 24 .

Examples:

 Factorial ( 3 ) 

Returns 6 , which = 3x2x1.

 Factorial ( 10 ; 3 ) 

Returns 720 , which = 10x9x8.

Comments:

One application of factorials is to determine how many unique ways a set of objects can be ordered. For instance, a set of three objects { A, B, C} can be ordered 3! = 6 ways: { ABC, ACB, BAC, BCA, CAB, CBA}.