I was thinking about writing a partial derivative macro that has a similar syntax to the Mathematica D function. (example)

The syntax could be like this:

`\D{f}{x}`

expands to`\frac{\partial f}{\partial x}`

`\D{f}{x,y}`

expands to`\frac{\partial^2 f}{\partial x\,\partial y}`

`\D{f}{{x,2},y}`

expands to`\frac{\partial^3 f}{\partial x^2\,\partial y}`

- et cetera for any number of derivatives.

Bonus points for an optional argument so that for instance

`\D[subscript]{f}{{x,2},y}`

expands to`f_{xxy}`

I looked at the `commath`

package but the syntax is a little tedious. For instance, to get `\frac{\partial^3 f}{\partial x^2\,\partial y}`

with that package I would need to do `\md{f}{3}{x}{2}{y}{}`

. And it doesn't generalize to three variables.

Before I dive in I thought I'd ask the hive and see what's been done.

## Best Answer

The

`cool`

package offers commands for writing partial derivates (and a lot of other stuff).A short example:

## Note

By default the last two of those will not work, as there is a bug in the package. This can be fixed by changing a

`\def`

to`\edef`

in line 2059 of`cool.sty`

, see Basic use of derivative with cool package fails with "Missing \endcsname inserted"