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).