Cylindrical Coordinate System
Definition
The coordinates of a point $p$ in coordinate space are represented as “the length $\rho$ of the line segment obtained by projecting the line between the origin and $p$ onto the $xy-$ plane” and “the angle $\phi$ formed by the line connecting the origin $O$ and the projection $p^{\prime}$ with the positive direction of the $x-$ axis” and “the value $z$ in the positive direction of the $z-$ axis of $p$” in what is called the cylindrical coordinate system.
Description
A set of points for a fixed $\rho, z$ forms a cylinder. Also known as the $(\rho, \phi, z)-$ coordinate system.