高中阶段,二次函数是最简单的非线性函数之一,它的性质活跃,经常作为其他函数的载体.在学习过抛物线等相关知识后,意识到二次函数和抛物线的天然联系,我们可以把某些简单二次函数看做是圆锥曲线,然后借助圆锥曲线的几何性质解决问题;同时,对于某些有关抛物线的最值问题,也可以转化为我们更加熟悉的二次函数问题,从而得到解决.在下例中,笔者先尝试用抛物线的性质解题(解法一),后尝试换元用二次函数求最值的思路 High school stage, quadratic function is one of the most simple nonlinear function, its nature is active, often as a carrier of other functions.After learning about the parabola and other related knowledge, aware of the quadratic function and the natural relationship of the parabola, we can Think of some simple quadratic functions as conics, then solve the problems with the help of the conic geometry, and at the same time, translate some of the most valuable problems with parabolas into our more familiar quadratic problems, In the following example, I first try to solve the problem with the nature of the parabola (solution one), after trying to find the value of the quadratic function to find the value of the idea