# Help Center > Our model

## What notation and symbols are commonly used here?

Many posts at Mathematics Stack Exchange include mathematical notation, written using $\mathrm\LaTeX$ commands surrounded by dollar signs. If you see dollar signs with what appears to be gibberish between them, it just means that MathJax, the math rendering we use, isn't working properly for you. There are two basic types of formula:

• Inline formulas are surrounded by single dollar signs. For example, $f(x) = ax^2 + bx + c$ renders as $f(x)=ax^2+bx+c$.

• Block formulas are surrounded by double dollar signs. For example, $$x = \frac{-b \pm \sqrt{b^2 - 4ac} }{2a}$$ renders, on a separate line, as $$x = \frac{-b \pm \sqrt{b^2 - 4ac} }{2a}.$$

Greek letters are mostly written by simply spelling them after a backslash with capitalization indicated by first letter. For example, $\alpha \beta \Gamma \Delta$ renders as $\alpha \beta \Gamma \Delta$.

For a quick tutorial and command reference, please see our MathJax quick reference page. See also our additional pointers and references.