椭圆 (9 12:22:51)

直线与椭圆相交P,Qp(x1,y1),Q(X2,Y2),因为M(1,1)为中点所以X1+X2=2*1=2,Y1+Y2=2*1=2x2/16+y2/4=1,x^2+4y^2=16x1^2+4y1^2=16,x2^2+4y2^2=16(x1^2-x2^2)+4(y1^2-y2^2)=0(y1-y2)/(x1-x2)=-(x1+x2)/[4(y1+y2)]=-1/4所以P...