第1题：设p(x,y)则由pa垂直pb得向量pa乘以向量pb=(4-x,-2-y)(-2-x,6-y)=0整理得动点p的轨迹x2-2x+y2-4y-20=0第2题设点c(x`,1-x`)点m(x,y)则-5+5+x`=3x 0+0+(1-x`)=3y整理得x`=3x x`=1-3y 即3x+3y-1=0当c(1,0)时,a,b,...