在解决数学问题时,如果问题所给对象不能进行统一处理时,我们就需要根据数学对象本质属性的相同点和不同点,将对象区分为不同种类,然后逐类进行解决,从而达到解决整个问题的目的,这一思想方法,我们称为分类讨论思想.分类讨论本质上是“化整为零,积零为整”的解题策略.引起分类讨论原因很多,通常有以下几种诱因. When solving the mathematical problem, if the problem can not be dealt with uniformedly, we need to solve the whole problem according to the same point and different point of the nature of the mathematical object, classify the objects into different kinds, and then class by class The purpose of this method of thinking, we call classified thinking .Classification discussion is essentially “classification is zero, the product of zero ” solution to the problem .Because the classification discussion for many reasons, usually the following incentives .