设点A到原点的距离为x,设点B到原点的距离为Y.得到：(x-2)/3=x/y2/(y-3)=x/y(x-2)/3=2/(y-3)x=6/(y-3)+2xy=6y/(y-3)+2y令y=k+3 k>=0xy=6(k+3)/k+2(k+3)=6+18/k+2k+6=2k+18/k+12=2(k+9/k)+12k+9/k=(k^2+9)/k=(k-3)^2/k...