Parametric Curve(s)

$$$ \forall\alpha\in\{0,2\pi\}\quad\; 2\leqslant\;k_{a}\;\leqslant8\quad\; 2\leqslant\;k_{b}\;\leqslant9$$$
$$$ \left \{ \begin{array}{r c l} \theta(\alpha)& = &(k_{a}\times\alpha) \\ r(\alpha)& = &0.24\times\cos{(k_{b}\cdot\alpha)} \end{array}\right .$$$