Gradient

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 [image].

 

x, y and z are the three dimensions of the cartesian coordinates.

 

[image]  Definition

 

The gradient is defined as the vector of partial derivatives:

 

[image]

 

The gradient gives us the rate of changes for all three components as a vector.

 

[image]

The gradient of the function f(x, y) = −(cos2x + cos2y)2 depicted as a projected vector field on the bottom plane (Source: Simiprof)

 

 

[image]  Example

 

Find the gradient of [image]

 

Derive partially:

 

[image] 

 

[image] is a constant with respect to x.

 

[image]

 

x is a constant with respect to y.

 

[image]

 

2 is a constant with respect to z.

 

 

The gradient of the vector is:[image]