## Precalculus (6th Edition) Blitzer

A polar equation is an equation that is represented by the use of variables $r\,\text{ and }\,\theta$.
Suppose the two polar equations are expressed as below: \begin{align} & r=2\cos \theta \\ & r=1+2\sin \theta \\ \end{align} where $r\,\text{ and }\,\theta$ are varibles.