This was another question where candidates’ performance was reported to be very poor. Majority of them could not complete the table of values correctly. The few who drew the graph correctly could not read from it. More work should be done by teachers on this area of the syllabus. The expected the table is as shown:
X |
0 |
30 |
66 |
90 |
120 |
130 |
180 |
210 |
240 |
Y |
2.0 |
2.2 |
1.9 |
1.0 |
-0.1 |
-1.2 |
-2.0 |
-2.2 |
-1.9 |
They were also expected to use the given scale and the table to draw the graph, locate the line y = 2.1 and use it to solve the equation, sin x = 2.1 – 2cos x, to obtain x = 9°, 45°. When x = 171°, y = – 1.75.