分类讨论是数学中的一种重要的思想方法和解题策略 .当问题所给的对象不宜进行统一的研究 ,或推理只有用分组的形式才能方便地表示出来时 ,就需要对研究的对象进行分类后对每一类分别研究 ,得出每一类的结果 ,最后综合各类的结果得到整个问题的结果 ,它是逻辑划分思想在解数学 Classification discussion is an important thinking method and problem solving strategy in mathematics. When the object given by the problem is not suitable for uniform research, or reasoning can only be expressed conveniently in a grouped form, it is necessary to conduct research on the object. After classifying, each type is studied separately, each type of result is obtained, and finally, the results of the various types are combined to obtain the results of the entire problem. It is the logical division of ideas in solving mathematics.