在日常生活和学习中,经常会遇到一些比较复杂的问题,对它们需要按照一定的标准分门别类地进行研究.这中间蕴涵的就是分类讨论思想.根据此思想所形成的数学方法就是分类讨论方法.分类讨论的原则有下面几个:(1)标准同一性原则:每一次分类的标准必须是同一的.(2)不遗漏原则:分类必须是完整的,不能出现遗漏. In daily life and learning, often encounter some more complex issues, they need to be studied according to a certain standard classification, which implies that the classification of thinking. According to the idea of ​​the formation of the mathematical method is to discuss the classification The principles of taxonomy discussion are the following: (1) Standard identity principle: the criteria of each classification must be the same. (2) The principle of omission: The classification must be complete and can not be omitted.