How to show math equations in general github's markdown(not github's blog)

Question

After investigating, I've found mathjax can do this. But when I write some example in my markdown file, it doesn't show the correct equations:

I have added this in the head of markdown file:

<script type="text/javascript" src="http://cdn.mathjax.org/mathjax/latest/MathJax.js?config=default"></script>

And type the mathjax statement:

\(E=mc^2\)，$$x_{1,2} = \frac{-b \pm \sqrt{b^2-4ac}}{2b}.$$

But github shows nothing for the math symbols! Please help me, thanks! Tell me how to show math symbols in github markdown pages.

Answer 1

But github show nothing for the math symbols! please help me, thanks!

GitHub markdown parsing is performed by the SunDown (ex libUpSkirt) library.

The motto of the library is "Standards compliant, fast, secure markdown processing library in C". The important word being "secure" there, considering your question :).

Indeed, allowing javascript to be executed would be a bit off of the MarkDown standard text-to-HTML contract.

Moreover, everything that looks like a HTML tag is either escaped or stripped out.

Tell me how to show math symbols in general github markdown.

Your best bet would be to find a website similar to yuml.me which can generate on-the-fly images from by parsing the provided URL querystring.

Update

I've found some sites providing users with such service: codedogs.com (no longer seems to support embedding) or iTex2Img. You may want to try them out. Of course, others may exist and some Google-fu will help you find them.

given the following markdown syntax

![equation](http://www.sciweavers.org/tex2img.php?eq=1%2Bsin%28mc%5E2%29&bc=White&fc=Black&im=jpg&fs=12&ff=arev&edit=)

it will display the following image

Note: In order for the image to be properly displayed, you'll have to ensure the querystring part of the url is percent encoded. You can easily find online tools to help you with that task, such as www.url-encode-decode.com

Answer 2

Markdown supports inline HTML. Inline HTML can be used for both quick and simple inline equations and, with and external tool, more complex rendering.

Quick and Simple Inline

For quick and simple inline items use HTML ampersand entity codes. An example that combines this idea with subscript text in markdown is: h_θ(x) = θ_o x + θ₁x, the code for which follows.

    h<sub>&theta;</sub>(x) = &theta;<sub>o</sub> x + &theta;<sub>1</sub>x

HTML ampersand entity codes for common math symbols can be found here. Codes for Greek letters here. An extensive list html entity codes to Unicode characters can be found here.

While this approach has limitations it works in practically all markdown and does not require any external libraries.

Complex Scalable Inline Rendering with LaTeX and Codecogs

If your needs are greater use an external LaTeX renderer like CodeCogs. Create an equation with CodeCogs editor. Choose svg for rendering and HTML for the embed code. Svg renders well on resize. HTML allows LaTeX to be easily read when you are looking at the source. Copy the embed code from the bottom of the page and paste it into your markdown.

<img src="https://latex.codecogs.com/svg.latex?\Large&space;x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}" title="\Large x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}" />

Expressed in markdown becomes

![\Large x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}](https://latex.codecogs.com/svg.latex?\Large&space;x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}) 

This combines this answer and this answer.

GitHub support only somtimes worked using the above raw html syntax for readable LaTeX for me. If the above does not work for you another option is to instead choose URL Encoded rendering and use that output to manually create a link like:

![\Large x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}](https://latex.codecogs.com/svg.latex?x%3D%5Cfrac%7B-b%5Cpm%5Csqrt%7Bb%5E2-4ac%7D%7D%7B2a%7D)

This manually incorporates LaTex in the alt image text and uses an encoded URL for rendering on GitHub.

Multi-line Rendering

If you need multi-line rendering check out this answer.