$$
z = \frac{x}{y}
$$$$
C_1 \quad= \quad c_2 + c_4^3
$$$$
y = \sqrt {x_1^2 + x_2^2 + x_3^2 + x_4^2}
$$$$
y = \sqrt [3]{x_1^2 + x_2^2 + x_3^2 + x_4^2}
$$$$
\overrightarrow{AB} = \overrightarrow{b} + \overrightarrow{a}
$$$$
c = a \cdot c
$$$$
\lim_{x\rightarrow0} \sin(x+y)
$$$$
\lim_{x\rightarrow0} \frac{\sin(x)}{x} = 1
$$$$
x^{\frac{1}{2}}
$$$$
\int_{0}^{\frac{\pi}{2}}
$$$$
\sum_{i=1}^{n}
$$$$
\prod_\epsilon
$$$$
a, b, c \neq \{ \{ a\}, b, c\}
%{ 和 } 是保留字需要‘\’转义
$$$$
1 + (\frac{1}{1-x^2})^3
$$$$
1 + \left(\frac{1}{1-x^2}\right)^3
$$$$
\left(\left(x+y\right)\left(x-y\right)\right)^2
$$$$
\big((x+y)(x-y)\big)^2
$$$$
\big((x+y)(x-y)\big)^2
$$$$
\big( \quad \big)
\Big( \quad \Big)
\bigg( \quad \bigg)
\Bigg( \quad \Bigg)
$$$$
\left[
\begin{matrix}
1 & 2 & 3 \\\
4 & 5 & 6 \\\
7 & 8 & 9
\end{matrix}
\right]
$$$$
\begin{bmatrix}
1&2&3\\\
4&5&6\\\
7&8&9
\end{bmatrix}
$$$$
\cdots
$$$$
\ddots
$$$$
\vdots
$$$$
\begin{bmatrix}
1&2&\cdots&4\\\
7&6&\cdots&5\\\
\vdots&\vdots&\ddots&\vdots\\\
8&9&\cdots&0
\end{bmatrix}
$$