数学中的“反客为主”也称更换主元,是指在解题过程中将两个字母或代数式主次互换,使问题达到消元、降次、化归的目的,将复杂问题简单化.此类方法在求恒成立问题,参数取值范围等问题时,往往能收到意想不到的效果.例1对于适合|p|≤2的任意一个实数,定义集合A={x|x~2+px+1>2x+p},求所有这样 In mathematics, “anti-domination” also called the replacement of the main element means that in the process of solving problems, the two letters or algebraic primary and secondary are interchangeable, so that the problem can be eliminated, reduced and changed, and the complex problem is simple Such methods can often receive unexpected results when establishing constant problems such as constants, parameter ranges, etc. Example 1 For any real number that fits | p | ≤2, the set A = {x | x ~ 2 + px + 1> 2x + p}, find all this