方法一:M(x,y),P(1,b)k(BM)=b/(1+1)=(y-b)/(x-1)b=2y/(1+x)|AM|=|AP|+|PA|√[(x+1)^2+y^2]=√{(x-1)^2+[y-2y/(1+x)]^2}+√[(1+1)^2+4y^2/(1+x)^2]方法二:tg∠MBA=y/(x-2)tg∠MAB=y/(x+1)