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3.5 Trigonometry (A-level only)

3.5 Trigonometry (A-level only)

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Question 85
i.

In a stability analysis for a rotating pendulum, the equilibrium angle α\alphaα in the interval 0<α≤π0 < \alpha \le \pi0<α≤π satisfies the equation

2cosec2α−5cot⁡α=5 2\text{cosec}^2 \alpha - 5\cot \alpha = 5 2cosec2α−5cotα=5

Determine all possible values for α\alphaα, giving your answers to 3 significant figures.

[4]
ii.

Prove the following trigonometric identity for all valid values of θ\thetaθ:

sin⁡8θsin⁡3θ−cos⁡8θcos⁡3θ≡sin⁡5θsin⁡3θcos⁡3θ \frac{\sin 8\theta}{\sin 3\theta} - \frac{\cos 8\theta}{\cos 3\theta} \equiv \frac{\sin 5\theta}{\sin 3\theta \cos 3\theta} sin3θsin8θ​−cos3θcos8θ​≡sin3θcos3θsin5θ​
[3]
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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