设A,B坐标分别是(x1,y1),(x2,y2),则所求M点到y轴距离为f(x1,x2)=(x1+x2)/2按照题目条件可得一下等式：y1^2=x1y2^2=x2(x1-x2)^2+(y1-y2)^2=3^2整理得：x1^2-2x1x2+x2^2+x1+x2-2√(x1x2)=9令φ(x1,x2)=x1^2-2x1x2+x2^2...