| Exam Board | Edexcel |
|---|
| Module | PMT Mocks (PMT Mocks) |
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| Topic | Product & Quotient Rules |
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5. Given that
$$y = \frac { 5 \cos \theta } { 4 \cos \theta + 4 \sin \theta } , \quad - \frac { \pi } { 4 } < \theta < \frac { 3 \pi } { 4 }$$
Show that
$$\frac { d y } { d \theta } = - \frac { 5 } { 4 ( 1 + \sin 2 \theta ) } , \quad - \frac { \pi } { 4 } < \theta < \frac { 3 \pi } { 4 }$$