P(x,y)
则B(2x-3,2y+1)
AC中点是(5/2,-2)
则BD中点也是(5/2,-2)
D(a,b)
则(a+2x-3)/2=5/2
(b+2y+1)/2=-2
a=8-2x
b=-5-2y
D在直线x-3y-1=0上
8-2x+15+6y-1=0
x-3y-11=0
P(x,y)
则B(2x-3,2y+1)
AC中点是(5/2,-2)
则BD中点也是(5/2,-2)
D(a,b)
则(a+2x-3)/2=5/2
(b+2y+1)/2=-2
a=8-2x
b=-5-2y
D在直线x-3y-1=0上
8-2x+15+6y-1=0
x-3y-11=0