9231 P12 - Jun 2025 - Q05 - 13 marks
4111
The curve C has polar equation \(r = \theta e^{\frac{1}{8}\theta}\), for \(0 \leq \theta \leq 2\pi\).
(a) Sketch C.
(b) Find the area of the region bounded by C and the initial line, giving your answer in the form \((p\pi^2 + q\pi + r)e^{\frac{1}{2}\pi} + s\), where \(p, q, r\) and \(s\) are integers to be determined.
(c) Show that, at the point of C furthest from the initial line,
\(\theta \cos \theta + \left( \frac{1}{8} \theta + 1 \right) \sin \theta = 0\)
and verify that this equation has a root between 5 and 5.05.
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