对于某些数学问题,若知所求结果具有某种确定的形式,则可引入一些尚待确定的系数来表示这种结果,通过变形与比较,建立起含有待定字母系数的方程(组),并求出相应字母系数的值,进而使问题获解,这种方法称为待定系数法,其在高中数学解题中具有广泛的应用,本文以待定系数法求数列通项公式为例说明,供参考. For some mathematical problems, if the result of the test has some definite form, some unknown coefficients can be introduced to represent the result. Through deformation and comparison, equations (groups) containing the coefficients of the unknown letters can be established, And get the value of the corresponding letter coefficient, and then the problem is solved, this method is called undetermined coefficient method, which has a wide range of applications in high school mathematics problem solving, this article to be determined coefficient method to solve the general formula as an example, for reference.