Math Formatting Guide

简单的数学编辑器

For formatting your questions, comments and solutions, you can useMarkdown. Using Markdown, you can bold or italicize things, add links and add a full blank line.

For formatting mathematics, we use LaTeX throughout the site.This means that you can format the math parts of your question, comment or solution by putting certain code inside these brackets$...$. The tables below contain some symbols that you will need most often, with the "code" in the left column, and the result on the right.

Markdown code Appears as

*italics*or_italics_ italics

**bold**or__bold__ bold

- bulleted
——列表

*Include an additional line break (empty row) before the start of a list.
*Make sure there is a space between the hyphen and list item text.

bulleted
list

1. numbered
2. list

numbered
list

paragraph 1

paragraph 2

paragraph 1

paragraph 2

> This is a quote

This is a quote

[example link](//www.parkandroid.com) example link

![Brilliant Logo](http://cl.ly/image/3m1O2L2k380t)

``` #By adding three tickmarks I've made a code block. while True: print "Solving problems now..." print "All done." ```

#By adding three tickmarks I've made a code block. while True: print "Solving problems now..." print "All done."

```python #By adding three tickmarks and a language name, I've added syntax highlighting. while True: print "Solving more problems..." print "Achievement unlocked." ```

#By adding three tickmarks and a language name, I've added syntax highlighting.whileTrue:print"Solving more problems..."print"Achievement unlocked."

|| 1 || 2 || 3 || 4 || || a || b || c || d ||

1	2	3	4
a	b	c	d

LaTeX Code	Appears as
`1 + 2`	$1 + 2$
`2 \times 3`	$2 \times 3$
`2 \cdot 3`	$2 \cdot 3$
`2 * 3`	$2 * 3$
`2^3`	$2^3$
`2^{34}`	$2^{34}$
`2^34`	$2^34$
`a_{i-1}`	$a_{i-1}$
`a_i-1`	$a_i-1$
`2^a_1`	$2^a_1$
`\frac {2}{3}`	$\frac {2}{3}$
`\frac 234`	$\frac 234$

LaTeX Code	Appears as
`\frac {1}{1 + \frac {1}{x}}`	$\frac {1}{1 + \frac {1}{x}}$
`\sqrt{2}`	$\sqrt{2}$
`\sqrt[3]{2}`	$\sqrt[3]{2}$
`1 \pm i`	$1 \pm i$
`\frac{-b \pm \sqrt{b^2-4ac}}{2a}`	$\frac{-b \pm \sqrt{b^2-4ac}}{2a}$
`2 < 3`	$2 < 3$
`2 \leq 3`	$2 \leq 3$
`3 \geq 2`	$3 \geq 2$
`2 \ neq 3`	$2 \ neq 3$
`\|x\|`	$\|x\|$
`\boxed{123}`	$\boxed{123}$

LaTeX Code	Appears as
`\infty`	$\infty$
`1 + 2 + 3 + \ldots + 10`	$1 + 2 + 3 + \ldots + 10$
`\sum_{i=1}^3`	$\sum_{i=1}^3$
`\prod_{i=1}^{31}`	$\prod_{i=1}^{31}$
`\displaystyle \sum_{i=1}^3`	$\displaystyle \sum_{i=1}^3$
`\log_2 4^6`	$\log_2 4^6$
`4 \equiv 2 \pmod{2}`	$4 \equiv 2 \pmod{2}$
`{6 \choose 3}`	${6 \choose 3}$
`\gcd(n,m)`	$\gcd(n,m)$
`\angle ABC = 90 ^ \circ`	$\angle ABC = 90 ^ \circ$

LaTeX Code	Appears as
`\sin \theta`	$\sin \theta$
`\cos 90^\circ = 0`	$\cos 90^\circ = 0$
`\tan \frac{\pi}{6} = \frac{1}{\sqrt{3}}`	$\tan \frac{\pi}{6} = \frac{1}{\sqrt{3}}$
`\alpha, \beta, \gamma, \ldots`	$\alpha, \beta, \gamma, \ldots$
`\overline{abba}`	$\overline{abba}$
`\underline{abba}`	$\underline{abba}$
`\rightarrow`	$\rightarrow$
`\Rightarrow`	$\Rightarrow$

For a more extensive list of LaTeX symbols, you may refer tothis Wikipedia page.

LaTeX Code	Appears as
`\ce{H2O}`	$\ce{H2O}$
`\ce{CrO4^2-}`	$\ce{CrO4^2-}$
`\ce{A <--> B}`	$\ce{A <--> B}$
`\ce{A ->[x_i] B}`	$\ce{A ->[x_i] B}$
`\ce{CO2 + C -> 2 CO}`	$\ce{CO2 + C -> 2 CO}$
`\ce{A\bond{~--}B\bond{~=}C\bond{-~-}D}`	$\ce{A\bond{~--}B\bond{~=}C\bond{-~-}D}$

Formatting Guide for Questions and Comments