- factorial
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—factorially, adv./fak tawr"ee euhl, -tohr"-/, n.1. Math. the product of a given positive integer multiplied by all lesser positive integers: The quantity four factorial (4!) = 4 · 3 · 2 · 1 = 24. Symbol: n!, where n is the given integer.adj.2. Math. of or pertaining to factors or factorials.3. of or pertaining to a factor or a factory.[1810-20; FACTOR + -IAL]
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For any whole number, the product of all the counting numbers up to and including itself.It is indicated with an exclamation point: 4! (read "four factorial") is 1 × 2 × 3 × 4 = 24. In order for certain formulas involving permutations and combinations to work, 0! is defined to be 1. Factorials are particularly useful in calculating the number of ways an event can occur, for example, the number of possible orders of finish in a race.* * *
in mathematics, the product of all positive integers less than or equal to a given positive integer and denoted by that integer and an exclamation point. Thus, factorial seven is written 7!, meaning 1 × 2 × 3 × 4 × 5 × 6 × 7. Factorial zero is defined as equal to 1.Factorials are commonly encountered in the evaluation of permutations and combinations and in the coefficients of terms of binomial expansions (see binomial theorem). Factorials have been generalized to include nonintegral values (see gamma function).* * *
Universalium. 2010.