|a|=5,|b|=5,a·b=24若（xa-yb）⊥a,则（xa-yb)·a=0即xa^2-y(a·b)=25x-24y=0若|xa-xb|=1,则|xa-xb|^2=x^2(a^2)-2x^2(a·b)+x^2(b^2)=1即25x^2-48x^2+25x^2=1得x=根号2/2或x=-根号2/2则y=25根号2/48或y=-25根号2/48...