Observation

The Chief Examiner reported that many candidates’ who attempted part (a) failed to recognize trigonometric value of the common angles and so lost out completely. However, part (b) was avoided by majority of the candidates’ and the performance of those who attempted it showed that much work is needed to be done by teachers in this topic.

In part (a), given that, cos⁡〖(2y – 16)^° 〗= 1/2. Solving gives 2y – 〖16〗^° = cos^(-1)⁡(1/2) gives 2y – 〖16〗^° = 〖60〗^° to get 2y = 〖76〗^° which yields y = 〖38〗^°. In part (b) (i) They were expected to draw a triangle ABC, with |AB| as 8cm, |BC| as 9cm and ∠ABC=〖75〗^°. Draw a straight line join point A and C together. Then Construction of arcs PA and PB with radius 4.5 to located P as shown:

In part (b) (ii) They were expected to measure CP as |CP| = 6.9 cm ± 0.1 and ∠ACB = 〖50〗^° ± 1.