函数的表示方法通常有三种:图象法、解析法、列表法.图象法是从“形”的角度表示两个变量之间的对应关系;解析法和列表法是从“数”的角度表示两个变量之间的对应关系,函数是“数”与“形”的统一,函数教学应突出“数形结合”的数学思想. There are usually three kinds of expressions of functions: image method, analytic method, and list method. The image method represents the correspondence between two variables from the perspective of “shape”; the analytical method and the list method are from the “number” The angle of “ represents the corresponding relationship between two variables, the function is the unity of ”number“ and ”shape“, and the function teaching should emphasize the mathematical idea of ​​”numeral combination".