利用函数的极值求最值

Using the ideas of function to get extreme value

在高中数学中,以下三种最值问题可用函数极值法求解:1.空间中异面直线的距离;2.圆锥曲线上的点到已知直线距离的最大、小值;3.通过换元求解最值。

In the Mathematics teaching of senior middle school, we can answer the follow-ing questions by the way of getting extrem value of function: 1. the distance between lines in dif-ferent space. 2. the manium and minium value of the distance between the point on the faper bendlines to known lines. 3. To get extreme value with enchanging elements.