你好，世界！
This is an inline (a^* = x-b^*) equation.
These are block equations:
[a^=x-b^] [ a^=x-b^ ]
[ a^* = x-b^* ]
These are block equations using alternate delimiters:
$$a^* = x-b^* $$
$$ a^* = x-b^* $$
$$ a^* = x-b^* $$
行内公式：$E = mc^2$
独立公式： $$ \int_{-\infty}^{\infty} e^{-x^2} dx = \sqrt{\pi} $$