若p(2,-1)为圆(x-1)²+y²=25的弦AB的中点,AB方程为

若p(2,-1)为圆(x-1)²+y²=25的弦AB的中点,AB方程为
若p(2,-1)为圆(x-1)²+y²=25的弦AB的中点,AB方程为

若p(2,-1)为圆(x-1)²+y²=25的弦AB的中点,AB方程为
xA+xB=2xP=2*2=4,yA+yB=2yP=-2
k(AB)=(yA-yB)/(xA-xB)=(y+1)/(x-2)
[(xA-1)^2+(yA)^2]-[(xB-1)^2+(yB)^2]=1-1
(xA+xB-2)*(xA-xB)+(yA+yB)*(yA-yB)=0
4-2+(-2)*(yA-yB)/(xA-xB)=0
1-(y+1)/(x-2)=0
AB:x-y-3=0