→ →
In this question, candidates were expected to compute vectors XY and YZ
from the given co-ordinates of the points.
→
XY = ( 6 - 4) = 2 , YZ = ( -2-6) = ( -8)
( 2 - 0) 2 ( 1 -2) (-1 )
→ →
With these, they can simplify 2XY + 3XZ. However, a good number of the candidates
→
had it that XY = √(6-4)2 + (2-0)2
i.e distance between X and Y which is very wrong.
→
In 7(b), XZ = -6 , thus /XZ/ = √(36+1) = √]37. Hence required unit vector is
1
1 (-6) or 1 (-6i + j)
√37 (-1) √37
Rationalizing the denominator gives √37 (-6) . Many candidates did not rationalize
37 (1)
the denominator hence, lost the final mark.