POR LIVIS VASQUEZ VALLE
The gradient usually indicates a direction in space which is seen as a variation of a particular property or physical quantity.
In other contexts gradient is used informally to indicate the existence of progressive or gradual variation in a specific area, not necessarily related to the physical layout of a particular size or ownership.
The gradient of a scalar field, which is differentiable in the neighborhood of a point, a vector is defined as the only means of finding the directional derivative in any direction as:
being a unit vector and the directional derivative of the address, which reports the rate of change of the scalar field to move around according to the following address:
An equivalent way to define the gradient is the only vector that when multiplied by any infinitesimal displacement, gives the differential of the scalar field:
With the above definition, the gradient is uniquely characterized. The gradient is expressed alternatively by using the nabla operator:
The divergence of a vector field is a scalar field, defined as the field flux vector per unit volume:
where S is a closed surface is reduced to a point on the boundary. The symbol represents the nabla operator.
This definition is directly related to the concept of flow field. As in the case of flow, if the divergence at a point is positive, says the field has springs. If the difference is negative, is said to have sinks. The most characteristic example is given by the electric charges, giving the divergence of the electric field, with positive charges and negative springs and sinks of the electric field.
They are called scalar field sources to the scalar field is obtained from the divergence of
The divergence of a vector field is related to the flow through the Gauss theorem and divergence theorem.
In vector calculus, curl, or rotor is a vector operator that shows the trend of a vector field to induce rotation around a point.
Mathematically, this idea is expressed as the limit of the circulation of the vector field, where the curve on integrating comes down to one point:
Here, ΔS is the surface area resting on the curve C, which reduces to a point. The result of this rotational limit is not complete (which is a vector), but only its component along the direction normal to ΔS and oriented according to the right hand rule. To get the full rotational three limits should be calculated considering three corners located in perpendicular planes.
Although the curl of a field about a point is not zero does not imply that the field lines rotate around that point and encieren. For example, the velocity field of a fluid flowing through a pipe (known as Poiseuille profile) has a non-zero curl everywhere except the central axis, although the current flows in a straight line
Starting from the definition by limited, it can be shown that the expression, in Cartesian coordinates, the curl is
can be expressed more concisely using the nabla operator as a vector product, calculable by determining: