(2/2) (2)求过P点的圆C的弦的中点的轨迹方程.
问题描述:
(2/2) (2)求过P点的圆C的弦的中点的轨迹方程.
答
圆C:(x+2)²+(y-6)²=16,设PC中点是M(x,y),则向量PM垂直向量CM,则向量数量积是0,得:(x,y-5)*(x+2,y-6)=0,化简得点M的轨迹方程x(x+2)+(y-5)(y-6)=0即:x²+y²+2x-11y+30=0【轨迹在圆内】