Specialist Mathematics · Unit 3 · Mathematical induction and trigonometric proofs · Trigonometric proofs using De Moivre’s theorem

Prove multi-angle trigonometric identities up to angles of 4𝑥 by equating parts using the binomial expansion and De Moivre’s theorem, e.g. cos(3𝑥) = 4 cos3(𝑥) − 3 cos(𝑥) and sin(3𝑥) = 3 sin(𝑥) − 4 sin3(𝑥). Specialist Mathematics 2025 v1.4

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