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7.2 Double Angle Formulae

7.2 Double Angle Formulae

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Question 2
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.

[2]
b.

Solve, for 0≤x≤1800 \leq x \leq 1800≤x≤180, the equation,

4cos⁡3x−3cos⁡x=−0.65 4\cos^3 x - 3\cos x = -0.65 4cos3x−3cosx=−0.65

Give your answers to 1 decimal place.

[4]
Markscheme

7.2 Double Angle Formulae Questions

  1. A Level
  2. /Maths
  3. /7.2 Double Angle Formulae

24 exam-style questions on Edexcel A Level Maths 7.2 Double Angle Formulae. Each one has a worked solution and a mark scheme showing where the marks go.

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