恒成立问题是高中数学中一个常见的难点问题,主要涉及不等式.笔者在解题过程中发现,也可利用分类讨论来解答一些恒成立问题,下面通过两个例子,和同学们一起分享体悟.例1若对任意实数x,不等式|x|≥ax恒成立,则实数a的取值范围为__.分析这是一道含参数的绝对值不等式恒成立问题,且不等式两边都涉及实数x.而解此题的关键去绝对值符号,仔细观察一下不等 Constantly established problem is a common high school mathematics problems, mainly related to inequality.In the process of solving the problem, I found that you can also use the classification of the discussion to answer some of the questions set up constant, the following two examples, and share their understanding. Example 1 If inequality | x | ≥ax is true for any real number x, then the real number a has a value range of __. Analysis This is a problem with constant absolute inequality with parameters, and the real number x is involved on both sides of the inequality. The key to solve this problem to absolute symbols, look carefully