Respuesta :

To convert a rectangular equation to polar forma, we use

[tex]x=r\cos (\theta),y=r\sin (\theta)[/tex]

In the equation x=18, we only have x, so

[tex]\begin{gathered} 18=r\cos (\theta) \\ r=\frac{18}{\cos(\theta)}=18\sec (\theta) \end{gathered}[/tex]