Latex 公式

$$ a \equiv b $$

$$ a \bmod b $$

$$ a \cdot b $$

$$ 0 \neq 1 \quad 1 \equiv 9 \quad (\bmod 2) $$

$$ a^2 + b^2 = c^2 $$
$$ C_a^b = C_{a \bmod p}^{b \bmod p} \cdot C_{a / p} ^{b / p} $$

$$ \sqrt{x^2} + \sqrt{x^2 + \sqrt{y}} = \sqrt[3]{k_i} - \frac{x}{m} $$

$$ \overline{a + b} \qquad \underline{a - b} $$

$$ \vec{a} + \overrightarrow{AB} = \overleftarrow{DE} $$

$$ \overbrace{a + 2 + 3 + \cdots + n}^{n} = \underbrace{a + b + \cdots + z}_{26} $$

$$ \lim_{x \to \infty}x^2_{22} - \int_1^5 x\mathrm{d}x + \sum_{n = 1}^{20}n^2 = \prod_{j = 1}^3y_i + \lim_{x \to -2} \frac{x - 2}{x} $$

$$ \hat{x} \\qquad \bar{x} \qquad \tilde{x} $$

$$ \begin{matrix} 1 & 2 & 3 \\\ 4 & 5 & 6 \\\ 7 & 8 & 9 \\\ \end{matrix} $$