Gradient
It is interesting to consider the rat of change for each direction of a vector in space. A particle could change its direction a different ways and different velocities. If you know its way in space you could predict where it would be then and then.
In mathematics we have a wonderful instrument to find out the rate of change by using the partial derivatives .
x, y and z are the three dimensions of the cartesian coordinates.
Definition
The gradient is defined as the vector of partial derivatives:
The gradient gives us the rate of changes for all three components as a vector.
The gradient of the function f(x, y) = −(cos2x + cos2y)2 depicted as a projected vector field on the bottom plane (Source: Simiprof)
Example
Find the gradient of
Derive partially:
is a constant with respect to x.
x is a constant with respect to y.
2 is a constant with respect to z.
The gradient of the vector is: