From 5501b216829ecb17b68dbaa3957257efc21279bc Mon Sep 17 00:00:00 2001
From: Zhao Xin <7176466@qq.com>
Date: Sun, 21 Jan 2024 19:50:40 +0800
Subject: [PATCH] =?UTF-8?q?=E6=9B=B4=E6=96=B0?=
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 概念/排列与组合.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/概念/排列与组合.md b/概念/排列与组合.md
index 9f657c7..1e06ed4 100644
--- a/概念/排列与组合.md
+++ b/概念/排列与组合.md
@@ -12,4 +12,4 @@ $$ A_{10}^3 = \underbrace{10\times9\times8}_{3个} = 720 $$
 
 $$ A_n^n = \underbrace{n\times(n-1)\times(n-2)\times\cdots\times1}_{n个} = n! （A_n^n叫全排列，n!叫做n的阶乘） $$
 
-$$ A_{n}^{m} = \underbrace{n\times(n-1)\times(n-2)\times\cdots\times(n-m+1)}_{m个} = \dfrac{n\times(n-1)\times(n-2)\times\cdots\times(n-m+1)\times(n-m)\times(n-m-1)\times(n-m-2)\times\cdots\times1}{(n-m)\times(n-m-1)\times(n-m-2)\times\cdots\times1} = \dfrac{n!}{(n-m)!}$$
+$$ \begin{align} A_{n}^{m} &= \underbrace{n\times(n-1)\times(n-2)\times\cdots\times(n-m+1)}_{m个} \\ &= \dfrac{n\times(n-1)\times(n-2)\times\cdots\times(n-m+1)\times(n-m)\times(n-m-1)\times(n-m-2)\times\cdots\times1}{(n-m)\times(n-m-1)\times(n-m-2)\times\cdots\times1} \\ &= \dfrac{n!}{(n-m)!} \end{align}$$