Polar Coordinates

3D version is cylindrical coordinates

$(x,y)=(r\cos \theta ,r\sin \theta )$

• Conversion from polar coordinates to rectangular coordinates

$(r,\theta )=\left(\sqrt{x^2+y^2},{\tan }^{-1}\left(\frac{y}{x}\right)\right)$

• Conversion from rectangular to polar coordinates

$J_{\text{polar}}=J_{\text{cylindrical}}=r$