104

I want to ask something that contains a mathematical formula.

How can I write the equation? Is there a page that shows the syntax?

I thought there must be some syntax like in Wikipedia or something...

  • 1
    See meta.stackexchange.com/questions/73504/… - but I don't think the syntax is implemented on SO – ChrisF Jan 28 '11 at 14:52
  • 13
    It's strange that stackoverflow does not support math formulas directly, like MathExchange or CrossValidate. – qed Sep 1 '13 at 14:30
64

I'm not sure why Simon deleted his answer, but it was right, you can use the Google Chart API. For example, this:

![foo+bar](https://chart.googleapis.com/chart?cht=tx&chl=foo%2bbar)

becomes:

foo+bar


Second formula:

![\sqrt{foo}](https://chart.googleapis.com/chart?cht=tx&chl=%5Csqrt%7Bfoo%7D)

becomes

\sqrt{foo}

  • Just to make this complete, an online TEXT editor: codecogs.com/latex/eqneditor.php – Yochai Timmer Jan 28 '11 at 17:42
  • This doesn't work well when you have more than 1 formula. – Yochai Timmer Jan 28 '11 at 19:40
  • @Yochai I just tried it in an edit; what issue are you having? – Michael Mrozek Jan 28 '11 at 19:49
  • tried to put 4 formulas, only the first showed. – Yochai Timmer Jan 28 '11 at 20:03
  • I need to substitute ) with %29 to make it work in preview when I type the answer. But even if I do so, it doesn't work when I save it and view it. @YochaiTimmer 's answer works for me. – Haozhun May 28 '13 at 7:26
  • 1
    This answer is now outdated, Stack Overflow now accepts LaTeX Phrases. (See Mehrad's answer) – Jan Moritz May 27 '14 at 19:35
  • 2
    @JanMoritz Stack Overflow still doesn't. Certain topic sites like Physics and Math Exchange do. – Asad Saeeduddin Jun 13 '17 at 4:58
49

Ok, best combination I found is doing something like what Michael suggested.
But it's easier to reference the link at the bottom.
So, go to this site: Online LaTex Equation Editor
Create your formula. Use this site and encode it for URL safety: URL Encoder/Decoder

Take the result and prepend it with the following URL: https://chart.googleapis.com/chart?cht=tx&chl=

Then reference it to your post:

This is a formula ![formula][1]
Another formula: ![another][2]

  [1]: https://chart.googleapis.com/chart?cht=tx&chl=%5Csum_%7B23%7D%5E%7B43%7D
  [2]: https://chart.googleapis.com/chart?cht=tx&chl=%5Csqrt%7B%5Cfrac%7B%5Cpartial%7D%7B%5Cpartial%20x%7D%7D

It will show like this:

This is a formula formula

Another formula: another

  • 1
    Unfortunately, the result is not as good as directly from LaTeX... – brimborium Aug 10 '12 at 10:26
  • +1 I was having trouble getting this to work using chart.googleapis.com although I was able to get this work using the URL encoded link from codecogs just fine. I was using it for this answer, any idea why? – Shafik Yaghmour Nov 30 '13 at 4:35
  • 1
    The latex editor you mentioned has an option for "URL (encoded)" that has been adequate to bypass the encoder for me so far. Saves one tab switch. – Mad Physicist Dec 19 '16 at 17:44
24

LaTeX Phrases

Some sites (mainly the scientific ones) use MathJax to render LaTeX. You can use single dollar signs to delimit inline equations, and double dollars for blocks:

The Gamma function satisfying $\Gamma(n) = (n-1)!\quad\forall n\in\mathbb N$ is defined through the Euler integral

$$ \Gamma(z) = \int_0^\infty t^{z-1}e^{-t}dt\,. $$

And you'll see the results as: enter image description here

To create a LaTeX phrase you can go to an online LaTeX Equation Editor.

  • 27
    It doesn't work on stackoverflow. – Mark Lakata Sep 6 '15 at 16:16
  • It works on a lot of stackexhange sites such as cross-validated, which are math intensive. – user350459 Dec 15 '17 at 16:54
  • 1
    It works on mathematics stack as well. – lenhhoxung Mar 6 at 16:27
13

1. Formulate your equation using the CodeCogs tool.

2. Right-click the generated image and select "Copy image location" or similar.

3. On Stack Overflow, insert the image as so: ![equation](imageUrl)

Thus:

![e=mc^2](https://latex.codecogs.com/gif.latex?e%3Dmc%5E2)

Becomes:

e=mc^2

5

Using WYSIWYG editor like Mathcha Editor

First, using this website to insert math equation (support import from latex)

Second, export to image/latex....to share Or login to the website and share without limitation (auto-generate a link). There is Mathcha Editor:

enter image description here

  • This is awesome.. – user350459 Dec 15 '17 at 16:35
  • Is this a opensource project? Based on neovim or something? i couldnt find information on github etc.. – user350459 Dec 15 '17 at 16:40

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