为什么我markdown里的数学公式全崩了？？？

Typecho博客

https://www.diyifanwen.com/fanwen/dangyuanxindetihui/2665516.htm
https://www.diyifanwen.com/fanwen/dangyuanxindetihui/2665516.htm
https://www.diyifanwen.com/fanwen/dangkexindetihui/2661093.htm
https://zhidao.baidu.com/question/585243762.html

try a try

$ \sum_{d|n} \mu(d) = [n==1] $

$ x $

$ \sum_{d|n} \phi(d) = n $

\[\sum_{d|n} \mu(d) = [n==1]\]

\[ \begin{equation} \sum_{d|n} \phi(d) = n \end{equation} \]

---

\[ \[\begin{aligned} x ={}& a+b+c+{} \\ &d+e+f+g \end{aligned}\] \]

ac is ok

#include
int main() {
      std::cout << "Hello!\n";
}

$ \sum_{k=1}^{log_{4}^{N}}{\frac{3}{4^{k}}}Nk $

\[ \begin{cases} 3x + 5y + z \\ 7x - 2y + 4z \\ -6x + 3y + 2z \end{cases} \]

\[ \begin{array} \overline{a+b+c} \\ \underline{a+b+c} \\ \overleftarrow{a+b} \\ \underleftarrow{a+b} \\ \underleftrightarrow{a+b} \\ \vec x = \vec{AB} \\ \overbrace {a+b}^\text{a,b} \\ a+\rlap{\overbrace{\phantom{b+c+d}}^m}b+\underbrace{c+d+e}_n+f \end{array} \]

\[ \begin{array} \sum_{d|n} \mu(d) = [n==1] \end{array} \]