| Exam Board | Edexcel |
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| Module | C12 (Core Mathematics 1 & 2) |
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| Year | 2017 |
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| Session | June |
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| Topic | Trig Equations |
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13. (a) Show that the equation
$$5 \cos x + 1 = \sin x \tan x$$
can be written in the form
$$6 \cos ^ { 2 } x + \cos x - 1 = 0$$
(b) Hence solve, for \(0 \leqslant \theta < 180 ^ { \circ }\)
$$5 \cos 2 \theta + 1 = \sin 2 \theta \tan 2 \theta$$
giving your answers, where appropriate, to one decimal place.
(Solutions based entirely on graphical or numerical methods are not acceptable.)