From 910eacbab9f6a521981c993e4ff073e630932df2 Mon Sep 17 00:00:00 2001 From: idealist999 <2974730459@qq.com> Date: Wed, 31 Dec 2025 20:53:23 +0800 Subject: [PATCH] vault backup: 2025-12-31 20:53:23 --- 编写小组/试卷/0103高数模拟试卷.md | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/编写小组/试卷/0103高数模拟试卷.md b/编写小组/试卷/0103高数模拟试卷.md index 68aea5a..824a21b 100644 --- a/编写小组/试卷/0103高数模拟试卷.md +++ b/编写小组/试卷/0103高数模拟试卷.md @@ -515,9 +515,9 @@ $$|x_{n+1} - x_n| \leq r |x_n - x_{n-1}| \leq r^2 |x_{n-1} - x_{n-2}| \leq \cdot 于是对任意正整数 $m > n$,有 $$ \begin{aligned} -|x_m - x_n| &\leq |x_m - x_{m-1}| + |x_{m-1} - x_{m-2}| + \cdots + |x_{n+1} - x_n| \\ -&\leq (r^{m-2} + r^{m-3} + \cdots + r^{n-1}) |x_2 - x_1| \\ -&= r^{n-1} \cdot \frac{1 - r^{m-n}}{1 - r} \cdot |x_2 - x_1| \\ +|x_m - x_n| &\leq |x_m - x_{m-1}| + |x_{m-1} - x_{m-2}| + \cdots + |x_{n+1} - x_n| \\[1em] +&\leq (r^{m-2} + r^{m-3} + \cdots + r^{n-1}) |x_2 - x_1| \\[1em] +&= r^{n-1} \cdot \frac{1 - r^{m-n}}{1 - r} \cdot |x_2 - x_1| \\[1em] &\leq \frac{r^{n-1}}{1 - r} |x_2 - x_1|. \end{aligned} $$