SPM Additional Mathematics 2017, Paper 1 (Question 1 – 3)


Question 3 (3 marks):
Diagram 3 shows vectors AB ,  AC  and  AD drawn on a square grid with sides of 1 unit.

Diagram 3

( a ) Find | BA |. ( b ) Given  AB = b ˜  and  AC = c ˜ , express in terms of  b ˜  and  c ˜   ( i )  BC , ( ii )  AD


Solution:
(a)
| BA |= 3 2 + 4 2 =5 units

(b)(i)
BC = BA + AC      = b ˜ + c ˜      = c ˜ b ˜

(b)(ii)
AD = AB + BD      = b ˜ +2 BC      = b ˜ +2( c ˜ b ˜ )      =2 c ˜ b ˜

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