The polar curves with the form:
[tex]\begin{gathered} r=a\pm b\sin (\theta) \\ r=a\pm b\cos (\theta) \end{gathered}[/tex]
are limacons. where a and b are constants. But when a and b are the same values, the polar curve is a cardioid.
So, the polar curve with the equation:
[tex]r=3-3sin(\theta)[/tex]
the polar curve is a cardioid because a and b are equal to 3.
