Question Number 4415 by Yozzii last updated on 22/Jan/16
$${Show}\:{that}\:{the}\:{curve}\:{defined}\:{by} \\ $$$${r}={sin}\mathrm{2}\theta−{sin}\mathrm{3}\theta\:\:\:\:\left(\mathrm{0}.\mathrm{2}\pi\leqslant\theta\leqslant\mathrm{0}.\mathrm{6}\pi\right) \\ $$$${is}\:{a}\:{closed}\:{loop}.\: \\ $$$$ \\ $$