1. markdown 嵌入代码
```
yum install composer
composer
composer create-project flarum/flarum . –stability=beta
```
需要在代码前后写入三次反引号
So tripple backticks, new line, code, new line, tripple backticks. Especially the new line before the finishing backticks is important.
示例：
positions = context.portfolio.positions
for equity in positions:
position = positions[equity]
print(position.sid)
2. markdown表达(向量,平均值,(线性回归，直线方程) y尖,无穷小,一阶导,二阶导)
| | 说明 |
|---|
| \vec{a} | \vec{a} | 向量 |
| \overline{a} | \overline{a} | 平均值 |
| \widehat{a} | \widehat{a} | (线性回归，直线方程) y尖 |
| \widetilde{a} | \widetilde{a} | 颚化符号 等价无穷小 |
| \dot{a} | \dot{a} | 一阶导数 |
| \ddot{a} | \ddot{a} | 二阶导数 |
\widetilde{Y}=F(x_1,x_2,...,x_n)
\overline{Y}