概率中排列的公式P(n,r)用英文怎么说?组合的公式C(n,r)呢?

来源:百度知道 编辑:UC知道 时间:2024/06/01 07:57:01

回答:

"P" is for "permutation". A permutation is an ordered sequence of elements selected from a given finite set, without repetitions, and not necessarily using all elements of the given set.

P(n, r) = n!/(n-r)!.

"C" is for "combination". A combination is an un-ordered collection of distinct elements, usually of a prescribed size and taken from a given set.

C(n, r) = n!/[r!(n-r)!].