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Trigonometry and Modelling

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Question 166
a.

By writing cos⁡3θ \cos 3\theta\,cos3θ as cos⁡(2θ+θ)\cos(2\theta + \theta)cos(2θ+θ) show that 4cos⁡3θ−3cos⁡θ=cos⁡3θ4\cos^3\theta - 3\cos\theta = \cos 3\theta4cos3θ−3cosθ=cos3θ

[2]
b.

Solve, for 0≤θ≤π0 \leq \theta \leq \pi0≤θ≤π, the equation,

cos⁡3θ=0.5 \cos 3\theta = 0.5 cos3θ=0.5

Give your answers in terms of π\piπ.

[4]
Markscheme

Trigonometry and Modelling Questions

  1. A Level
  2. /Maths
  3. /Trigonometry and Modelling

348 exam-style questions on Edexcel A Level Maths Trigonometry and Modelling, covering 7.1 Addition Formulae, 7.2 Double Angle Formulae, 7.3 Solving Trigonometric Equations, 7.4 Simplifying a cos x +- b sin x, 7.5 Proving Trigonometric Identities, and 7.6 Modelling with Trigonometric Functions. Each one has a worked solution and a mark scheme showing where the marks go.

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