If you have a parametric equation grapher, graph the equations over the given intervals.
$$x=2 \cos t+\cos 2 t, \quad y=2 \sin t-\sin 2 t ; \quad 0 \leq t \leq 2 \pi$$
What happens if you replace 2 with -2 in the equations for $x$ and $y ?$ Graph the new equations and find out.