\[(r, \theta , \phi )\]
is Cartesian coordinates.\[x= r sin \theta cos \phi\]
\[x= r sin \theta sin \phi\]
\[x= r cos \theta\]
Spherical Coordinates
We need three number to define a point in three dimensional space, but ordinary Cartesian coordinates with mutually perpendicular axes is not always the best system to use. One alternative is the system of spherical coordinates. This is especially useful when problems have spherical symmetry or distance from a point. below