这个问题粗看起来很简单:设 P(x,y)点为圆锥曲线上一点,利用两点间距离公式便可求得最值.但是,此种方法运算过程中会遇到较大的困难.其实这只要联想到直线上一点到两定点的距离之和(差)最小(大)的问题,这个问题也就不难解决了.下面介绍一 This problem looks rough: Let P (x, y) be a point on a conic curve, use the distance formula between the two points to get the maximum value. However, this method will encounter greater difficulties in the calculation process. Actually, as long as this is associated with the problem that the sum (distance) of the distance between one point and two fixed points on the straight line is the smallest (large), this problem is not difficult to solve.