数学预备知识
初日辉煌
·
·
个人记录
数学预备知识
---
### $1.$关系符
#### $\space\space\space\space$因为：$\because
\space\space\space\space所以：\therefore
\space\space\space\space使得：st.
2.运算符
\space\space\space\space阶乘：!
\space\space\space\space$ $x$的阶乘写作$x!,x!=x\cdot(x-1)\cdot (x-2)\cdot \ldots \cdot2\cdot1
\space\space\space\space取余数/模运算：\%或mod
#### $\space\space\space\space$ 同余：$x\equiv k\pmod n
#### $\space\space\space\space$求和：$\sum
\space\space\space\space$ $\sum_{i=1}^na_i=a_1+a_2+\ldots+a_n
\space\space\space\space$ $\sum_{x=l}^rf(x)=f(l)+f(l+1)+\ldots+f(r)\space\space(r\geq l)
\space\space\space\space求积：\prod
\space\space\space\space$ $\prod_{i=1}^na_i=a_1\cdot a_2\cdot\ldots\cdot a_n
\space\space\space\space$ $\prod_{x=l}^rf(x)=f(l)\cdot f(l+1)\cdot\ldots\cdot f(r)\space\space(r\geq l)
\space\space\space\space