The array environment is an analog of tabular that uses math mode. I can't test now, but I think that regular LaTeX allows $...$ inside tabular. Probably MHF does not allow dollar signs inside formulas.
I used this code
\begin{tabular}{|c|c|c|c|c|} \hline f(x) & - &+ &- &+ \\ \hline x & - & + & + & + \\ \hline (2x-3) & - & -& + & + \\ \hline (x-2) & - & - & - & + \\ \hline & (infinity,0) & (0,3/2) & ( 3/2, 2 ) & (2, infinity) \\ \hline \end{tabular}
To generate this table in MHF
The problem is inside the tabular environemt it will not take the math commands any longer.
I tried $$ and the tex boxes again inside, but they both gave errors. Is this just a limitation of MHF Latex, or is there a way? Also on a different note, does anyone know what packages are preloaded?