Originally Posted by

**Smugleaf** Hello, I'm having a problem involving polar coordinates and writing an equation using rectangular coordinates. Here are the directions and the problem:

The letters r and θ represent polar coordinates. Write each equation using rectangular coordinates (x,y).

r=(3)/[3-cos(θ)]

I attempted to work on the problem, but I eventually got stuck. Here is my attempt:

r = (3)/[3-cos(θ)]

r[3-cos(θ)] = 3

3r - rcos(θ) = 3

[3r - rcos(θ)]^{2 }= 3^{2}

9r^{2} - 6r^{2}cos(θ) + r^{2}cos(θ) = 9

9r^{2} - 5r^{2}cos(θ) = 9

After that, I'm not exactly sure on what I need to do. I would turn the r^{2} into x^{2} + y^{2}, but I'm not sure what to do with the 5r^{2}cos(θ).