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3.5 Trigonometry (A-level only)

3.5 Trigonometry (A-level only)

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Question 46
a.

By writing cos⁡3ϕ \cos 3\phi\,cos3ϕ as cos⁡(2ϕ+ϕ)\cos(2\phi + \phi)cos(2ϕ+ϕ), show that cos⁡3ϕ=4cos⁡3ϕ−3cos⁡ϕ\cos 3\phi = 4\cos^3 \phi - 3\cos \phicos3ϕ=4cos3ϕ−3cosϕ.

[2]
b.

Solve, for 0≤ϕ≤1800 \leq \phi \leq 1800≤ϕ≤180, the equation,

12cos⁡3ϕ−9cos⁡ϕ=1.5 12\cos^3 \phi - 9\cos \phi = 1.5 12cos3ϕ−9cosϕ=1.5

Give your answers to 1 decimal place where necessary.

[4]
Markscheme

3.5 Trigonometry (A-level only) Questions

  1. A Level
  2. /Maths
  3. /3.5 Trigonometry (A-level only)

225 exam-style questions on WJEC A Level Maths 3.5 Trigonometry (A-level only), covering 3.5.1 Trigonometry (A-level only), 3.5.2 Trigonometry (A-level only), 3.5.3 Trigonometry (A-level only), 3.5.4 Trigonometry (A-level only), 3.5.5 Trigonometry (A-level only), 3.5.6 Trigonometry (A-level only), 3.5.7 Trigonometry (A-level only), and 3.5.8 Trigonometry (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.

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