7.2 Double Angle Formulae
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a.

By writing cos⁡3x \cos 3x\,cos3x as cos⁡(2x+x)\cos(2x + x)cos(2x+x), show that cos⁡3x=4cos⁡3x−3cos⁡x\cos 3x = 4\cos^3 x - 3\cos xcos3x=4cos3x−3cosx

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b.

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

4cos⁡3x−3cos⁡x=32 4\cos^3 x - 3\cos x = \frac{\sqrt{3}}{2} 4cos3x−3cosx=23​​

Give your answers in terms of π\piπ.

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7.2 Double Angle Formulae Questions

Practise Edexcel A Level Maths 7.2 Double Angle Formulae with exam-style questions for A Level Maths. 24 questions, matched to the Edexcel A Level Maths (9MA0) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.

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7.2 Double Angle Formulae Questions

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