不等式的证明方法有很多,课本中只介绍了几种常用的方法,随着学习的深入,题目综合性的不断提高,比较法、综合法和分析法越来越不能满足解题的需要,丰富与扩充不等式的证法已迫在眉睫,本文以学生常做的一道复习题为例, 引入并解剖一些证明方法的证题机理. 题目设x+y+z=a,x2+y2+z2=a2/2,a>0,求证:x,y,z都不小于零 There are many ways to prove inequality, and only a few commonly used methods are introduced in the textbooks. With the deepening of the study, the comprehensiveness of the topics has been continuously improved, and the comparison, synthesis, and analysis methods are increasingly unable to meet the needs of problem solving. The proof of expansion of inequality has become imminent. This article takes a review question often done by students as an example to introduce and dissect the proof mechanism of some proof methods. The title is x+y+z=a,x2+y2+z2=a2/ 2, a> 0, verify: x, y, z are not less than zero