Episode 4 — Trigonometric Compound & Double Angles

Double Angles

Learners will be able to:

• Identify the double angle formulae for sin 2θ and cos 2θ. • Apply the double angle expansion for sin 2θ to evaluate expressions involving sine functions. • Use the double angle expansion for cos 2θ to express cosine functions in terms of sine or cosine only. • Simplify trigonometric expressions using the double angle formulae, including expressing sin 3x in terms of a single trig ratio of angle x. • Evaluate expressions involving half angles using the double angle formulae.