# Vectors Short Questions (Question 1 - 3)

Question 1:
Given that O (0, 0), A (3, 4) and B (9, 12), find in terms of the unit vectors,  $\underset{˜}{i}$ and  $\underset{˜.}{j}$
(a) $\stackrel{\to }{AB}$
(b) the unit vector in the direction of $\stackrel{\to }{AB}$

Solution:
(a)

(b)

Question 2:
Given that A (3, 2), B (4, 6) and C (m, n), find the value of m and of n such that   $2\stackrel{\to }{AB}+\stackrel{\to }{BC}=\left(\begin{array}{c}12\\ -3\end{array}\right)$
Solution:

10 + m = 12
m = 2

2 + n3
n5

Question 3:
Diagram below shows a rectangle OABC and the point D lies on the straight line OB.

It is given that OD = 3DB.

Solution: