THINKING 1. Given: | a | = 20, | b | = 16 and | a + b | = 13. Find | a - b |. Illustrate your reasoning and conclusion with an appropriate diagram. [6] 2. In the parallelogram ABCD, W is the midpoint of BC and the points X and Y are the points of the trisection of AD. Express each of the following vectors in terms of P and q . M B C a) BY q p b ) MY A X Y D3. The diagram shows a square based right pyramid. State a single vector equal to each expression. A a) AB + BD b) AB - AD d) AE - CD E e) AC + DE + BE E C f) AE - CD + BD - AD