KNOWLEDGE

$${\mathrm{e}}^{i}x=cosx+isinx$$$$\mathrm{e}=\sum _{n=0}^{\mathrm{\infty }}{\displaystyle \frac{1}{n!}}$$$$\underset{x\to 0^{+}}{lim}{\displaystyle \frac{1}{x}}=\mathrm{\infty }$$$$M=\left[\begin{array}{ccc}\frac{5}{6}& \frac{1}{6}& 0\\ \frac{5}{6}& 0& \frac{1}{6}\\ 0& \frac{5}{6}& \frac{1}{6}\end{array}\right]$$$$A_{m,n}=\left(\begin{array}{cccc}{a}_{1,1}& a_{1,2}& \cdots & a_{1,n}\\ a_{2,1}& a_{2,2}& \cdots & a_{2,n}\\ ⋮& ⋮& \ddots & ⋮\\ a_{m,1}& a_{m,2}& \cdots & a_{m,n}\end{array}\right)$$