函数是描述事物运动变化规律的数学模型.研究函数就是要研究事物运动变化过程中变量间的依存关系,它包含三方面的内容:一是函数的概念:二是函数模型——表格,图象和解析式;三是函数的变化规律——函数的性质.在中学,函数的学习主要分为三个阶段:一是初中学习函数的描述性定义,并了解正比例函数、反比例函数、一次函数、二次函数和它们的图象与性质:二是本章函数概念的形式化定义、函数的基本性质与初等函数(I)和(II);三是选修系列中 Function is a mathematical model that describes the law of the movement of things.Research function is to study the interdependence between variables in the process of changing things, which contains three aspects: First, the concept of function: the second is the function model - form, image And analytical expression; Third, the law of the function - the nature of the function.In middle school, the function of learning is divided into three stages: First, the descriptive definition of junior high school learning function, and understand the proportional function, inverse function, a function, Quadratic functions and their image and nature: the second is the formal definition of functional concepts in this chapter, the basic properties of the function and the elementary functions (I) and (II); the third is the elective series