From a5b15fef87be7ac3a8f9212fcc3430861529a6c6 Mon Sep 17 00:00:00 2001
From: Zhao Xin <7176466@qq.com>
Date: Wed, 7 Sep 2022 21:34:13 +0800
Subject: [PATCH] gitpush

---
 问题/等差数列.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/问题/等差数列.md b/问题/等差数列.md
index 2091185..c4df8d5 100644
--- a/问题/等差数列.md
+++ b/问题/等差数列.md
@@ -13,7 +13,7 @@ $$ a_n = a + (n-1)d \tag{等差数列通项公式} $$
 
 由等差数列通项公式可以得到以下公式：
 
-$$ n = \dfrac{a_n}{d} + 1 \tag{已知首项尾项及公差求项数}$$
+$$ n = \dfrac{a_n - a}{d} + 1 \tag{已知首项尾项及公差求项数}$$
 
 等差数列求和公式：