Formulas wrapped with a single $ will always render left-justified:

$E = mc^2$ => $E = mc^2$ \n$E = mc^2$\n => $E=mc^2$

Formulas wrapped with double $$ will render in the centered format shown below only If the following conditions are met:

• The formula is on it's own line.
• NO characters including all whitespace characters other than "\n", are on the formula's line before the first $$ or after the second $$.

$$E = mc^2$$ => $E = mc^2$

The math below renders centered because the formula does not share its line with any other characters: \n$$E = mc^2$$\n => $E = mc^2$

Note: If ANY character shares a line with a formula, (see space before "\n") it will render left-justified even if wrapped with double $$:

\n$$E = mc^2$$\n => $E = mc^2$