LaTex笔记

$$\begin{gathered} \frac{L{}_2{}^1⨂_4^3 \\ \frac{1}{3} \\ 4}{3} \\ \sqrt{6} \\ \sqrt[7]{49} \\ f(x_1,x_2,\dots ,x_n)=x_1^2+x_2^2+\cdots +x_n^2 \\ \overrightarrow{a}\cdot \overrightarrow{b}=0 \\ {\int }_0^1{x}^2\mathrm{d}x \\ \underset{n\to +\mathrm{\infty }}{lim}\frac{1}{n(n+1)} \\ \sum _{i=0}^n\frac{1}{i^2} \\ \alpha \beta \gamma \mathrm{\Gamma }\delta \mathrm{\Delta }ϵ\text{Epsilon} \\ \pm \times ÷\mid \nmid \cdot \circ \ast ⨀⨂\le \ge \ne \approx \equiv \sum \prod \coprod \\ \mathrm{\varnothing }\in \notin \subset \supset \subseteq \supseteq \bigcap \bigcup \bigvee \bigwedge ⨄⨆ \\ \mathrm{\perp }\mathrm{\angle }{30}^{\circ }\sin \cos \tan \cot \sec \csc \\ \prime \int \iint \iiint ⨌lim\mathrm{\infty }\mathrm{\nabla } \\ \because \therefore \mathrm{\forall }\mathrm{\exists }\ne \ngtr \not\subset \\ \hat{y}\check{y}\breve{y} \\ \overline{a+b+c+d} \\ \underset{―}{a+b+c+d} \\ \stackrel{2.0}{\overbrace{a+\underset{1.0}{\underbrace{b+c}}+d}} \\ \uparrow \downarrow \Uparrow \Downarrow \to \leftarrow \Rightarrow \Leftarrow ⟶⟵⟸⟹ \\ \{\begin{array}{l}{a}_{1}x+b_{1}y+c_{1}z=d_1\\ a_{2}x+b_{2}y+c_{2}z=d_2\\ a_{3}x+b_{3}y+c_{3}z=d_3\end{array} \\ \begin{array}{ccc}1& 0& 0\\ 0& 1& 0\\ 0& 0& 1\end{array} \end{gathered}$$

$$\begin{gathered} \wedge \mathrm{合}\mathrm{取} \\ \vee \mathrm{析}\mathrm{取} \\ \mathrm{\neg }\mathrm{否}\mathrm{定} \\ \to \mathrm{蕴}\mathrm{含} \\ \leftrightarrow \mathrm{双}\mathrm{条}\mathrm{件} \\ \Rightarrow \mathrm{推}\mathrm{出} \\ \iff \mathrm{等}\mathrm{价} \\ \mathrm{\forall }\mathrm{任}\mathrm{意} \\ \mathrm{\exists }\mathrm{存}\mathrm{在} \end{gathered}$$

两个quad空格	a b		两个m的宽度
quad空格	a b		一个m的宽度
大空格	a b		1/3m宽度
中等空格	a;b		2/7m宽度
小空格	a,b		1/6m宽度
没有空格	ab
紧贴	a!b		缩进1/6m宽度