ECZ 2026 · GCE Paper 1 — Trigonometry
Triangle ABC is right angled at B, BCD is a straight line and cos ACD = -1213. Find the value of sin CAB.
- A. 513
- B. -1213
- C. 1213
- D. 512
Verified working — step 1
ACD sits on the straight line BCD, so it is the supplement of angle ACB inside the triangle: the cosines are the same size with opposite signs. Then read the sides of triangle ABC.The full step-by-step working and final answer are included with Premium — checked against ECZ marking standards.
Original examination question © Examinations Council of Zambia. Worked solution and commentary © G12 Titan — not to be reproduced without permission.
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