在有理数学习的过程中,我们常会遇到含字母的实数比较大小的问题,同学们对于此类问题往往不知如何下手.事实上,解决这类问题的关键在于“分段”.这里以一题为例,介绍一下如何分段.题目试比较实数a与1/a的大小.分析解这类题一般分三步:第一步:取特殊值.一般取使两个数无意义的值 In the process of rational number learning, we often encounter the problem of comparing the size of real numbers containing letters. Students often do not know how to start with such problems. In fact, the key to solving such problems lies in “segmentation”. Here is a question. For example, introduce how to segment. The title tries to compare the size of real a and 1/a. Analyze the solution to this kind of question is generally divided into three steps: The first step: take a special value. Generally take two values ​​that make no sense