https://www.jianshu.com/p/e6d2368e451a
[\
]
(2x+3y=34)
[\
]
[2x+3y=34
\
2x+3y=frac{1}{3}
]
[sqrt[3]{x}=sqrt{y}
]
[Longrightarrow
\
Longleftarrow
]
求和
[sum_{i=1}^n i^2
\
\
egin{matrix} sum_{i=1}^n i^2 end{matrix}
\
\
sumlimits_{d|n} a_d * a_frac{n}{d}
]