A markdown editor bug? cannot show corrected formula with mathjax

Question

I use markdown editor and mathjax to write math formula, sometimes it cannot show corrected form, here is the example:

$$(A_2)\int_{-\infty}^{+\infty} dx $$

Is this a markdown editor's bug?

When I use Basic Editor,it is OK.

Furthermore, in the Preview of markdown editor, the formula shows OK, but when I finish the editor, the answer shows problem.

Help me, please.

Comments

the problem comes from underscore _

Answer 1

Here is a solution for pagedown preview:
http://stackoverflow.com/questions/11228558

But as far as I know there is no solution for php markdown.
Please let me know if you found any solution.