| Exam Board | OCR |
|---|
| Module | Further Pure Core 1 (Further Pure Core 1) |
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| Year | 2020 |
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| Session | November |
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| Topic | Complex numbers 2 |
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5 By expanding \(\left( z ^ { 2 } + \frac { 1 } { z ^ { 2 } } \right) ^ { 3 }\), where \(z = e ^ { \mathrm { i } \theta }\), show that \(4 \cos ^ { 3 } 2 \theta = \cos 6 \theta + 3 \cos 2 \theta\).