Notation in vector
Vector calculus concerns differentiation and integration of vector or scalar fields particularly in a three-dimensionalEuclidean space, and uses specific notations of differentiation. In a Cartesian coordinate o-xyz, assuming a vector field A is 
, and a scalar field 
is 
.
First, a differential operator, or a Hamilton operator ∇ which is called del is symbolically defined in the form of a vector,
where the terminology symbolically reflects that the operator ∇ will also be treated as an ordinary vector.
∇φ
-
Gradient: The gradient
of the scalar field is a vector, which is symbolically expressed by the multiplication of ∇ and scalar field ,
