二次函数在区间上的最值以及零点问题是高考对二次函数考察的核心内容.关于这两方面的问题,通法是对参数分类讨论,观察对称轴与所给区间之间的关系,再借助二次函数图像进行求解.此法计算复杂,需讨论情况繁多,对解题带来很大不便.下面借助函数方程的思想,数形结合求解“已知最值,求解参数取值范围”及“已知函数在区间上的零点情况,求解参数取值范围”这两类二次问题. The quadratic function of the quadratic function in the interval and the zero point is the core of the quadratic function of the college entrance examination.About these two aspects, the common method is to discuss the parameters, the relationship between the symmetry axis and the given interval, And then solve it with the help of quadratic function image.This method is computationally complicated and needs to be discussed in many ways, which brings great inconvenience to solving the problem.With the help of the idea of ​​functional equation, Range “and ” Known function in the interval of zero situation, solving the parameter value range "These two types of quadratic problems.