The Wolfram Language makes it easy to take even the most complicated derivatives involving any of its huge range of differentiable special functions.

Define a function with one variable, :

To find , type f'[x] and press :

This method works for any order; just add more primes:

Or use D. Its first argument is the function and its second argument is the variable:

For higher-order derivatives using D, the second argument is a list, {variable,order}:

Define a function with two variables, :

Take the first derivative with respect to and the second with respect to by combining the two forms (single variable and list):

The Heaviside theta function is treated as if it had an infinite pulse at zero, where it is undefined:

The HeavisideTheta function has special derivative properties:

This plots the HeavisideTheta (green) and DiracDelta (red) functions: