AB=2e1+ke2 (1)
CB=2e1-3e2 (2)
若A,B,C三点共线
=> AB = mCB ( m is a constant)
2e1+ke2=m(2e1-3e2)
=>
2=2m and k=-3m
=>m=1 and k=-3m
=>k=-3
AB=2e1+ke2 (1)
CB=2e1-3e2 (2)
若A,B,C三点共线
=> AB = mCB ( m is a constant)
2e1+ke2=m(2e1-3e2)
=>
2=2m and k=-3m
=>m=1 and k=-3m
=>k=-3