### Partial derivative

The partial derivative of a function *f* of a number of variables, is the derivative in which just one of the variables is treated and the others as constants

in which the symbol ∂ is used.

##### Explanation

Other notations are

These different notations are often used interchangeably. That seems confusing, but in practice it is quite usefull.

##### Example 1

The most general form of the Schrödinger equation is

where is the differential operator.

##### Example 2

The laplacian of a function *f* in ℝ^{n} coordinates is

where is the differential operator.