Parsing a derivative

Evidently, the math-expressions library is smart enough to parse a student’s answer as a derivative operator, e.g. if the student types “dy/dx” into the answer box, the corresponding function tree labels it as “derivative_leibniz”. However, the instructor-side parser doesn’t do this, leading to the same string giving two different function trees, and thus being ultimately labeled as unequal and the validation is rejected.

For an example, hit f12 to open up the console and then put “dy/dx = 3x” in the following answer box. The console will display the tree generated for the student’s answer, and the one generated by the instructor (click the arrow to expand the top level of the tree to see the issue). You can also verify the tex file has the same string as the desired letters. I’ve also included a \frac{dy}{dx}=3x\verb version of it in the second answer box.