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Trigonometric Identities and Equations

Trigonometric Identities and Equations

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Question 35
a.

Show that the equation

2sin⁡2x=4cos⁡2x−cos⁡x 2\sin^2 x = 4\cos^2 x - \cos x 2sin2x=4cos2x−cosx

can be expressed in the form

6cos⁡2x−cos⁡x−2=0 6\cos^2 x - \cos x - 2 = 0 6cos2x−cosx−2=0
[3]
b.

Hence, solve the equation

2sin⁡22θ=4cos⁡22θ−cos⁡2θ 2\sin^2 2\theta = 4\cos^2 2\theta - \cos 2\theta 2sin22θ=4cos22θ−cos2θ

giving all values of θ \theta\,θ between 0∘ 0^\circ\,0∘ and 180∘180^\circ180∘, correct to 1 decimal place.

[5]
Markscheme

Trigonometric Identities and Equations Questions

  1. A Level
  2. /Maths
  3. /Trigonometric Identities and Equations

41 exam-style questions on Edexcel A Level Maths Trigonometric Identities and Equations, covering 10.1 Angles in all four Quadrants, 10.2 Exact Values of Trigonometric Ratios, 10.3 Trigonometric Identities, 10.4 Solving Trigonometric Equations, 10.5 Harder Trigonometric Equations, and 10.6 Equations and Identities. Each one has a worked solution and a mark scheme showing where the marks go.

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