| Exam Board | Edexcel |
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| Module | P2 (Pure Mathematics 2) |
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| Year | 2019 |
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| Session | June |
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| Topic | Reciprocal Trig & Identities |
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9. (a) Show that the equation
$$\cos \theta - 1 = 4 \sin \theta \tan \theta$$
can be written in the form
$$5 \cos ^ { 2 } \theta - \cos \theta - 4 = 0$$
(b) Hence solve, for \(0 \leqslant x < \frac { \pi } { 2 }\)
$$\cos 2 x - 1 = 4 \sin 2 x \tan 2 x$$
giving your answers, where appropriate, to 2 decimal places.