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@ -228,28 +228,6 @@ $$f(a) = f(b) = 0，\quad f'_+(a)f'_-(b) > 0，$$
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```
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>[!example] 例3
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设 $f(x)$ 在 $[0, 1]$ 上具有二阶导数，且满足
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$$f(0) = 0, \, f(1) = 1, \, f\left(\frac{1}{2}\right) > \frac{1}{4}$$证明：
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(1)至少存在一点 $\xi \in (0, 1)$，使得 $f''(\xi) < 2$；
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(2)若对一切 $x \in (0, 1)$，有 $f''(x) \neq 2$，则当 $x \in (0, 1)$ 时，恒有 $f(x) > x^2$。
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```text
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```
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## **拉格朗日中值定理**
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### **原理**
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若函数 f(x) 满足两个条件:
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