Some problems of inline formulas

[nixnehc]

When I was used Markdown to write posts, only \\( E = mc^2 \\) code can drive this inline formula in the final webpage, but the code $ E = mc^2 $ didn't.

The question is that in my Markdown parser, say Typora, only $ E = mc^2 $ can be previewed, while \\( E = mc^2 \\) cannot.

How should I to solve this problem?

Thanks a lot!