分类讨论是一种重要的数学思想方法 ,当问题所给对象不能进行统一研究时 ,就需要对研究的对象进行分类 ,将整体问题划分为局部问题 ,把复杂问题转化为单一问题 ,然后分而治之、各个击破 ,最后综合各类的结果得到整个问题的解答 .所以分类讨论题中有题 ,步骤繁琐 ,过程冗长 ,如 Classification discussion is an important method of thinking in mathematics. When problems cannot be studied uniformly, they need to classify the research objects, divide the overall problem into local problems, turn complex issues into single problems, and divide and conquer, Each break, and finally the results of the various types of comprehensive answers to the entire question. Therefore, there are questions in the classification of the discussion questions, the procedures are cumbersome, the process is lengthy, such as