啊大大大

二级标题

士大夫啊士大夫

def abc():
    print("阿士大夫的撒发")

public static void main(){
    System.out.println("哈哈");
}

ls -l

emoji表情：😕

$\alpha$
$\beta$
$\chi$
$\Delta$
$\Gamma$
$\Theta$

\alpha \tag1

(1)
$\frac{abc}{xyz}$

(2)

\frac{abc123}{xyz123}

|

\|

\bigcap\bigcup\bigoplus\bigotimes\sum\int\oint\iint

\sin^2(\theta) + \cos^2(\theta) = 1

\sum_{n=1}^\infty k

\int_a^bf(x)\,dx

\lim\limits_{x\to\infty}\exp(-x) = 0

\begin{matrix} 0&1&2\\ 3&4&5\\ 6&7&8\\ \end{matrix}

\begin{Bmatrix} 0&1&2\\ 3&4&5\\ 6&7&8\\ \end{Bmatrix}

f(x) = \begin{cases} 2x,\,\,x>0\\ 3x,\,\,x\le0\\ \end{cases}

\begin{Vmatrix} 0&1&2\\ 3&4&5\\ 6&7&8\\ \end{Vmatrix}