Section 20.1 Graphs in Polar Coordinates
Functions expressed in polar coordinates can be graphed. For the function \(r(\phi)\text{,}\) for each value of \(\phi\text{,}\) an angle measured counterclockwise from the \(x\)-axis, plot the distance \(r(\phi)\text{,}\) measured outward from the origin.
For example, conic sections can be described in the form
\begin{equation*}
r(\phi) = \frac{\alpha}{1+\varepsilon\cos(\phi-\delta)}
\end{equation*}
as shown in Figure 20.1.