The curve \(C\) has parametric equations
$$x = \cos^2 t$$
$$y = \cos t \sin t$$
where \(0 \leq t < \pi\)
- Show that \(C\) is a circle and find its centre and its radius.
[5]
% Figure 1 shows a sketch of C with point P, rectangle R with diagonal OP
\includegraphics{figure_1}
Figure 1
Figure 1 shows a sketch of \(C\). The point \(P\), with coordinates \((\cos^2 \alpha, \cos\alpha \sin \alpha)\), \(0 < \alpha < \frac{\pi}{2}\), lies on \(C\). The rectangle \(R\) has one side on the \(x\)-axis, one side on the \(y\)-axis and \(OP\) as a diagonal, where \(O\) is the origin.
- Show that the area of \(R\) is \(\sin\alpha \cos^3 \alpha\)
[1]
- Find the maximum area of \(R\), as \(\alpha\) varies.
[7]
[Total 13 marks]