| Exam Board | CAIE |
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| Module | P3 (Pure Mathematics 3) |
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| Year | 2013 |
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| Session | November |
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| Topic | Parametric equations |
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4 The parametric equations of a curve are
$$x = \mathrm { e } ^ { - t } \cos t , \quad y = \mathrm { e } ^ { - t } \sin t$$
Show that \(\frac { \mathrm { d } y } { \mathrm {~d} x } = \tan \left( t - \frac { 1 } { 4 } \pi \right)\).