分类讨论思想是根据研究对象性质上的差异,分不同情况进行全面考察.这既是一种数学解题思想,也是一种解题策略.分类讨论应全面考虑,必须做到既不重复也不遗漏,以防错解的发生.下面举例分析,希望能够引起同学们的高度重视,有利于提高我们思维的严密性,提升我们的解题技能.一、因图形的位置不确定应分类讨论 The idea of ​​category discussion is based on the differences in the nature of the research object, a comprehensive study of different conditions .This is not only a mathematical problem-solving ideas, but also a problem-solving strategy .Classification should be considered, must be neither duplication nor omission , To prevent the occurrence of the wrong solution. The following example analysis, hoping to arouse the attention of the students, is conducive to improving the rigor of our thinking, improve our problem-solving skills. First, due to the location of graphics should be classified discussion