# How can I incorporate good-looking mathematical exposition into my question/answer?

How can I incorporate good-looking mathematical exposition into my question/answer?

• I've created this FAQ entry because of this question Mar 20 '14 at 10:52

NOTE: Code Golf now supports MathJax (see the other answer), so this is no longer accurate; however, the other advice in the post is worth keeping around.

codegolf.SE does not use MathJax, because its load time is too high (see discussion). But although there is not built-in support for LaTeX, you can visualize mathematical formulae in various ways

## Images

You can include mathematical formulae as images. There a basically three ways how to get such an image:

• Use the preview of math.SE to create your formula, make a screenshot and crop it to the right size.
• Create a LaTeX document on your computer, make a screenshot and crop it to the right size.
• Use command line tools (see this question)
• Use MathURL to create an image of the equation (fastest option for images)

## Symbols

Many math symbols are also available as plain text. You can create your formula by using copy-and-paste:

The most basic symbols that you might need are:

• Arrows: ← ↓ → ↑ ↔ ↵ ⇐ ⇓ ⇒ ⇑ ⇔
• Sets: ∈ ∉ ∅ ⊆ ⊂ ⊄ ∪ ∩
• Relations: ≠ ≤ ≥ ≈
• Logic: ¬ ∧ ∨ ∃ ∀
• More: ∫ ∞ ε Δ ⋅

Note that most platforms offer some kind of extended character input palette which makes this input method easier. (e.g. Character Viewer in OSX, Character Map in Windows)

## Pure ASCII

While this is the least elegant-looking option, it produces results intelligible to anyone who understands the corresponding mathematical symbols. Handy if you want to put equations in your source code comments.

• asciiTeX - Binary for Windows only, but it is available on Homebrew for OSX and should build for Linux.
• Awesome! I've added a few details, will put in more later when I have more time. Mar 20 '14 at 15:14
• Did you copy the symbols idea from me? Yay. I would like to suggest the Window's Snipping tool for making screenshots. It works just like a program I made, but it's better because it is easier to snip an image. I was overjoyed when a professor showed this program to us for use in our Labs. Mar 31 '14 at 3:40
• As far as posting images go, I think a simpler option than screenshots is MathURL Jun 7 '14 at 23:02
• As MathURL doesn't support https, I highly recommend (And with heavy bias) using a-ta.co May 16 '17 at 0:01
• @ATaco Is this link outdated, or this page just down at the moment? Jul 13 '17 at 4:32
• @musicman523 Just down for a quick maintenance, should be back up shortly. Jul 13 '17 at 4:32
• Since MathJax is now enabled, this answer is no longer accurate in this regard. Aug 30 '18 at 10:16

Code Golf, as of June 20th 2018, has $$\\LaTeX\$$ enabled on both main and meta sites. A much more complete guide on how to use Mathjax can be found here, but here are the basics for those not familiar:

• To include inline formula, enclose the formula with $: $\sin x^2\ is $$\\sin x^2\$$ • For displayed formula, use $$: $$\frac {\log n} \pi$$ is $$\frac {\log n} \pi$$ • For subscripts and superscripts, use _ and ^: x_2 ($$\x_2\$$) and 5^2 ($$\5^2\$$) • Most operations only work on the next character: 2^10 ($$\2^10\$$). In order to group multiple parts together, use {}: 2^{10} ($$\2^{10}\$$). Notice the difference between $$\x_i^2\$$ and $$\x_{i^2}\$$ (x_i^2 and x_{i^2}) • Fractions. There are three ways to display fractions: • \frac{a+1}{b+1}: $$\\frac{a+1}{b+1}\$$ • \over for more complex fractions: {x^2+5x-6 \over 7sin(y^3)} is $$\{x^2+5x-6 \over 7\sin(y^3)}\$$ • \cfrac for continued fractions: \cfrac a b is $$\\cfrac a b\$$ • Sums and products are \sum and \prod respectively: $$\\sum\$$, $$\\prod\$$. Use a superscript argument for the value on top and a subscript for the value underneath: \sum_{i=0}^{10} i is $$\\sum_{i=0}^{10} i\$$ • Special characters, such as {, _ etc. can be escaped by prefixing with a backslash: $$\\{ \_ \$$. A backslash should be \backslash • Some common symbols: \lt \gt \le \leq \ge \geq \times \div \pm \cdot \circ \to \infty are $$\\lt \gt \le \leq \ge \geq \times \div \pm \cdot \circ \to \infty\$$ • Some common functions: \sin \tan \cos \lim are $$\\sin \tan \cos \lim\$$. You can use subscripts to change limits: \lim_{x \to 0} is $$\lim_{x \to 0}$$ Some slightly less common things: Matrices Use $$\begin{matrix}…\end{matrix} In between the \begin and \end, put the matrix elements. End each matrix row with \\, and separate matrix elements with &. For example, $$\begin{matrix} 1 & x & x^2 \\ 1 & y & y^2 \\ 1 & z & z^2 \\ \end{matrix}$$  produces $$\begin{matrix} 1 & x & x^2 \\ 1 & y & y^2 \\ 1 & z & z^2 \\ \end{matrix}$$ Aligned equations Often people want a series of equations where the equals signs are aligned. To get this, use \begin{align}…\end{align}. Each line should end with \\, and should contain an ampersand (&) at the point to align at, typically immediately before the equals sign. For example, \begin{align} x^2 + 2x - 1 & = x^2 + 2x + 1 - 2 \\ & = (x + 1)^2 - 2 \end{align}  produces \begin{align} x^2 + 2x - 1 & = x^2 + 2x + 1 - 2 \\ & = (x + 1)^2 - 2 \end{align} Definitions by cases Use \begin{cases}…\end{cases}\$. End each case with a \\, and use & before parts that should be aligned. For example,

$$f(x) = \begin{cases} f(x-1) + f(x-2), & \text{ if } x > 2 \\ 1, & \text{ if } x = 1 \text{ or } x = 2 \end{cases}$$


produces

$$f(x) = \begin{cases} f(x-1) + f(x-2), & \text{ if } x > 2 \\ 1, & \text{ if } x = 1 \text{ or } x = 2 \end{cases}$$