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分类讨论是初中数学中常用的重要思想方法之一,同时也是一种重要的解题策略,应用及其广泛,也是中考试题中作为考查学生分析问题和解决问题的常见题型.但是此类题往往综合性强、难度较大,学生总有畏难心理,出现解题困难.下面本人根据教学实践介绍几种技巧以破解讨论难题.一、数形结合,直观求解利用几何图形的直观性能巧妙地将数量关系与空间图形有机的结合起来,有时也可以简化甚至回避问题的讨论.例1若|x-1|+|2+x|=3,则x的取值范围是.
Classification discussion is one of the important thinking methods commonly used in junior high school mathematics, but also an important problem-solving strategy, its application and its wide range, and is also a common problem in exam questions for students to analyze and solve problems. Often comprehensive, difficult, students always have the fear of difficulties, there is a problem-solving difficulties.According to the teaching practice below, I introduce several techniques to solve the problem of discussion.First, the combination of figures, visual intuitive use of the intuitive performance of the geometry cleverly The number of relations with the spatial graph organic combination, and sometimes can simplify or even avoid the discussion of the problem.Example 1 If | x-1 | + | 2 + x | = 3, then the range of x is.