Answer:
[tex]r=\frac{9\cos \theta}{\sin^2 \theta}[/tex]
Step-by-step explanation:
The given equation in rectangular coordinates is;
[tex]y^2=9x[/tex]
We use the relation;
[tex]x=r\cos \theta[/tex]
and
[tex]y=r \sin \theta[/tex]
This implies that;
[tex](r \sin \theta)^2=9(r \cos \theta)[/tex]
[tex]r^2 \sin^2 \theta=9r \cos \theta[/tex]
Divide through by r to get;
[tex]r \sin^2 \theta=9\cos \theta[/tex]
Divide both sides by [tex]\sin^2 \theta[/tex]
[tex]r=\frac{9\cos \theta}{\sin^2 \theta}[/tex]
