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Trigonometry and Modelling

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Question 154
a.

By writing sin⁡3θ \sin 3\theta\,sin3θ as sin⁡(2θ+θ)\sin (2\theta + \theta)sin(2θ+θ) show that sin⁡3θ=3sin⁡θ−4sin⁡3θ\sin 3\theta = 3\sin\theta - 4\sin^3 \thetasin3θ=3sinθ−4sin3θ

[2]
b.

Solve, for 0≤θ≤1800 \leq \theta \leq 1800≤θ≤180, the equation,

3sin⁡θ−4sin⁡3θ=k 3\sin\theta - 4\sin^3 \theta = k 3sinθ−4sin3θ=k

where 0<k<10<k<10<k<1.

Give your answers in terms of kkk.

[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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