A(x1,y1)B(x2,y2)T((x1+x2)/2,(y1+y2)/2)M(-1,0)x1^2-y1^2=1x2^2-y2^2=1(x1+x2)^2/4+(y1+y2)^2/4+(x1+x2)=0直线AB垂直于MT,斜率之为-1(y2-y1)/(x2-x1)*((y1+y2)/2)((x1+x2)/2+1)=-1解得x1+x2=-3T点坐标(-3/2,+-根号3/2)所以MT斜率为+-根号3/3所以AB斜率为+-根号3 l方程:y=+-根号3x-+根号3