设P1(x1,y1）P2（x2,y2）中点为（x,y）根据题意即x1+x2=2x,y1+y2=2y且(y1-y2)/(x1-x2)=(y-1)/(x-1)椭圆方程x²/16+y²/4=1即x²+4y²=16代入P1P2坐标x1²+4y1²=1x2²+4y2²=1两式...