Paper 2 · Trigonometry
⏱ Tested in 1 exam question since 2023
Lesson 4 of 8
Trigonometry 1.4 – SinA = Cos(90-A)
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- Show that the two non-right angles of a right-angled triangle add to 90°
- Derive sin A = cos(90° − A) and cos A = sin(90° − A) from the opp/adj swap
- Rewrite sin of any angle as cos of its complement (e.g. sin 70° = cos 20°)
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- 2023 Paper 2 Q2(a) — prescribed proof — derive the sin(A + B) compound-angle identity from the cos(A − B) ide…
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