| Exam Board | OCR |
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| Module | C3 (Core Mathematics 3) |
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| Year | 2007 |
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| Session | January |
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| Topic | Harmonic Form |
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5
- Express \(4 \cos \theta - \sin \theta\) in the form \(R \cos ( \theta + \alpha )\), where \(R > 0\) and \(0 ^ { \circ } < \alpha < 90 ^ { \circ }\).
- Hence solve the equation \(4 \cos \theta - \sin \theta = 2\), giving all solutions for which \(- 180 ^ { \circ } < \theta < 180 ^ { \circ }\).