Often, the mathematician needs to represent mathematical expressions such as differential equations. So that this is not a nightmare, the mathematician Andrew Parsloe created a package that offers super useful commands. This post will deal with such commands, show the results without the package and with the package to see the differences. Let’s go!

In the first place, we need to load the package diffcoeff. I recommend using the last version, i.e., version 3.0. It’s available on TeX Live distribution for all platforms like GNU/Linux, Mac OS X, Windows 10, and so on.

The diffcoeff package works thanks to $\LaTeX 3_{\varepsilon}$ kernel.

Update 3.1 on 09/03/2019

From now on, this package is compatible with differentials of a vector-valued function. Motivate for this question on popular forum of $\LaTeX$. Check out the section six of diffcoeffdocumentation on CTAN for this update.

Minimal Working example

\documentclass{article}
\usepackage[ISO]{diffcoeff}	% Important load diffcoeff package.
%\usepackage{amsmath}

\begin{document}
$\diff{y}{x}$			% Appears the left hand side of differential equation.
\end{document}