ABSTRACT
Many calculations in science can be greatly simplified by using, instead of the familiar rectangular Cartesian coordinate system, another kind of system which takes advantage of the relations of symmetry involved in particular considered problems. Spherical coordinates are a special case of the orthogonal curvilinear coordinate system. There are at least nine special orthogonal coordinate systems; the most common and useful ones are the cylindrical and spherical coordinates. The integration of a vector, which is a function of a single scalar u, can proceed as an ordinary scalar integration. Gauss theorem, also called theorem of divergence, relates the surface integral of a given vector function with the volume integral of the divergence of that vector. Stokes theorem relates the line integral of a vector function with the surface integral of the curl of that vector. The divergence and curl of a vector field play very important roles in science.
