在求函数自变量的取值范围时 ,关键是分析函数的存在形式 .在初中阶段 ,函数的存在形式最基本的有三种 :整式、分式和二次根式 ,我们把这三种函数叫做求定义域的基本函数 .求函数自变量取值范围的方法 ,一般是根据函数有意义的条件列出有关不等式再求解即可 .一、基本函数1 .整 In the process of finding the range of values ​​of the function’s independent variables, the key is to analyze the existence of the function. In the junior high school, there are three basic forms of the function: integral, fractional, and quadratic root. We call these three functions Define the basic function of the domain. The method of finding the range of values ​​of the function’s independent variables is generally based on the meaningful conditions of the function to list the relevant inequalities and then solve it. First, the basic function 1. The whole