### How to fix an equation created with DragMath

Number of replies: 4I installed and used the DragMath. Everything was working properly. However, I created an math equation. I put into the course section. But, I wrote wrong this math equation. Question:

How can I load this math equation to fix it in the DragMath program?

Before to put this problem here, I read the dragMath documentation, however I don't find anything related with it.

TIA

Mónico

### Re: How to fix an equation created with DragMath

### Re: How to fix an equation created with DragMath

Cheers

### Re: How to fix an equation created with DragMath

Dear Mónico,

This really is the Million-£ question.

We considered carefully how we might achieve this as it is obviously something we all need to do. But there is no simple solution. As an example consider the latex code

$x(t+1)$

If we sent this back to DragMath would we end up with multiplication or function application? This is a classic dilemma and is at the heart of the problems which people have in trying to automatically read LaTeX script.

People have given this problem some very serious thought.

http://www.cs.berkeley.edu/~fateman/papers/parsing_tex.pdf

The point of DragMath was to be able to have many output formats and for people to be able to modify these. So if we did have a "reload LaTeX" option we would need to have a parser somewhere to interpret this.

We included the JEP parser within DragMath to parse any text you type in a box. Alex has been working on being able to load DragMath with an expression and use this parser to interpret it. This is so that students using the STACK computer aided assessment system, (which uses Maxima syntax) can have exactly the functionality you describe for this output format. It was not compiled into the first release but is high on our list.

Hence, we want to do this but in order to do so we need

(1) to fix the "load expession" section of DragMath and

(2) find a LaTeX to "something with content" parser.

Another solution would be to store a representation of the expression which we could load back into DragMath as some kind of "alt" text. This might well be using the JEP parser solution. Currently in the context of LaTeX and Moodle I do not see how this might work, but am very open to suggestions.

It is not hopeless, but is may be a lot of work!

Sorry not to be able to provide this in phase one.

Chris

### Re: How to fix an equation created with DragMath

My best wishes.

Mónico