Sperical Coordinate System
Definition
The coordinates of a point in coordinate space are represented by “the distance between the origin and ,” “the angle between the line connecting the origin and and the positive direction of the axis,” and “the angle between the projection of the line connecting the origin and on the plane and the positive direction of the axis.” This is called the spherical coordinate system.
Explanation
The set of points for a fixed forms a sphere. Therefore, the distance from the origin is denoted as , following the initial of radius. It is also referred to as the coordinate system.