diff --git a/素材/罗尔定理与拉格朗日中值定理.md b/素材/罗尔定理与拉格朗日中值定理.md
index bee8105..20c295a 100644
--- a/素材/罗尔定理与拉格朗日中值定理.md
+++ b/素材/罗尔定理与拉格朗日中值定理.md
@@ -105,4 +105,4 @@ $$
 $$
 f'(\xi_1)-f'(\xi_2) = f''(\xi)(\xi_1-\xi_2) < 0
 $$
-故 $f(x_1+x_2)-f(x_2)-f(x_1) < 0$，即 $f(x_1+x_2) < f(x_1)+f(x_2)$。、
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+故 $f(x_1+x_2)-f(x_2)-f(x_1) < 0$，即 $f(x_1+x_2) < f(x_1)+f(x_2)$。
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