极值是中学数学中重要知识点之一,在实际生活中很多“最大”“最小”和“最优”问题都可以归结为极值问题.而这些问题的通常都是在某些特定环境和范围内产生的,这就自然出现了带限制条件的极值问题,即在条件B下,求对象A的最大或最小问题.此类问题广泛出现于各种奥数竞赛和高考命题,是中学数学学习的难点之一,解决这类问题的关键是如何合理地将将条件B应用于A的最大或最小问题的中.下面介绍几类带限制 Extremum is one of the important knowledge points in high school mathematics, and many “maximum”, “minimum” and “optimal” problems in real life can be summed up as extreme value problems, which are usually In some special circumstances and the scope of the generated, which naturally appeared with the limit of the extreme value problem, that is, under the condition B, the maximum or minimum problem of object A. Such problems occur in a wide range of Mathematical Olympiad competitions and College entrance examination proposition, is one of the difficulties of high school mathematics learning, the key to solve these problems is how to apply condition B to the maximum or minimum of A. In the following,