Refresher - Representing Equations in Terms of Polar Coordinates

Coordinate Conversion The polar coordinate $(r, θ)$ are related to the rectangular coordinate $(x, y)$ as follows.
$x = r cos θ$	$tan θ = \frac{y}{x}$
$y = r sin θ$	$r^{2} = x^{2} + y^{2}$

We can use the above formulas to convert equations from one coordinate system to the other.