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函数自变量的取值范围是初中数学里面的重点内容之一,全国各地每年的中考试题中经常出现。那么,怎么注意函数自变量的取值范围呢?一方面由函数解析式本身确定;另一方面,要考虑具体问题的实际意义。本文试从这两个方面加以归纳。一、已知函数式,求自变量的取值范围按教材和大纲要求,同学们练习时接触的是整式、分式、根式、指数等所表示的函数,注意函数式中自变量的取值范围的根据是:
The range of function arguments is one of the key contents of junior high school mathematics, which is often found in the middle school exams throughout the country each year. So, how to pay attention to the range of function arguments? On the one hand by the function to determine the resolution itself; the other hand, to consider the practical significance of specific issues. This article tries to summarize these two aspects. First, the known function, the range of independent variables According to the requirements of teaching materials and syllabus, the students practice is exposed by the integral, fractional, radical, index, etc. expressed function, pay attention to the value of the function argument The rationale for the range is: