Exercises — Addition, double-angle and half-angle formulae

All the worked exercises of the chapter, in order of appearance in the book: computing trigonometric values with the addition formulae, applying the double-angle formulae, linearisation, half-angle formulae and a proof of the triple-angle formula.

• Sine of 105° and cosine of 165°
• 3
• Linearising sin²α cos²α
• Tangent of 22.5°
• Triple-angle formula for the cosine