In MapleTA (2.51) we are using an algorithm to generate the components of a formula. The components are then combined and the MathML function called to render the formula. We have discovered a problem that occurs when a negative number follows an operator, i.e., 5a+4b+-7c.
Here is a simplified example of the question code:
question=a is $a
b is $b
If $a, $b, or both are negative, the following error is generated:
com.maplesoft.server.router.MapleSyntaxException: on line 7, syntax error, `-` unexpected:
In Maple-10 this works fine. If and equation that has a negative number following an operator, i.e., 5+-3, Maple will render it correctly as 5-3.
I've tried different arrangements of parenthesis with no success. This seems to be a bug in MathML library.