Question

If a and b are position vectors of A and B respectively the position vector of a point C on AB produced such that `vec(AC)=3 vec(AB)` is
A. 3 a -2b
B. 3b -2a
C. 3b +2a
D. 2a - 3b

Answer 1

Correct Answer - B
Let the position vector for C be c.
Clearly , B divides AC internally in the ratio 1:2
` therefore b=(2a +1.c ) /(2+1)implies c=3b-2a`