Writing math

Both AsciiMath and Tex are supported in this documentation. The default is AsciiMath. This markdown:

$$
E = mc^2
$$

will be rendered as a centered display formula:

You can specify formulas written in TeX as follows:

$$ tex
    \frac{x}{5} = 2y
$$

which will be rendered as follows:

Inline math is supported, too, and defaults to AsciiMath. This will work:

Circle radius is related to its circumference according to formula $ r = C/(2pi) $

and will be rendered as follows:

Circle radius is related to its circumference according to formula

AsciiMath also understands certain TeX constructs, so this will work, too:

Circle radius is related to its circumference according to formula $ r = \frac{C}{2\pi} $

results in:

Circle radius is related to its circumference according to formula

Justification

You can justify block math:

$$ justify = left
E = mc^2
$$

will be rendered on the left (similar with right):

Scrolling behavior

For extra long formulas, scrolling behavior might be implemented like this:

$$ width = null, overflow = scroll, tex
\int_{0}^{\infty}\frac{\sqrt{x^{2}+1}\,\left(\sum_{n=1}^{20}\frac{\sin(nx)+\cos(nx)}{n^{2}+x^{2}}\right)\,\left(\prod_{k=1}^{12}\frac{x^{2}+k^{2}}{x^{2}+k+\frac12}\right)}{\left(1+\frac{x^{2}}{2}+\frac{x^{4}}{3}+\frac{x^{6}}{4}+\frac{x^{8}}{5}\right)\left(\sqrt[3]{x+1}+\sqrt[5]{x+2}+\ln(x+3)+e^{-x/7}\right)}\,dx+\sum_{m=1}^{25}\frac{\left(\frac{m^{2}+3m+1}{m^{3}+1}\right)^{2}\left(\sqrt{m+1}+\sqrt[3]{m+2}+\frac{1}{m+4}\right)}{\left(1+\frac{1}{m}\right)\left(1+\frac{1}{m^{2}}\right)\left(1+\frac{1}{m^{3}}\right)}=\prod_{r=2}^{18}\left(1+\frac{1}{r^{2}}+\frac{1}{r^{3}}+\frac{1}{r^{4}}\right)
$$

will render a math formula that can be horizontally scrolled:

Note that the other possible value for ‘overflow’ would be ‘truncate’ but this is of little use.

Line break treatment

Note that line breaks can be treated as separate new lines when rendered. Normally math like this:

$$
    tan(x) = sin(x) / cos(x)
    cot(x) = cos(x) / sin(x)
$$

would be rendered like this:

but you can force it render on separate lines using the ‘nl’ option:

$$ nl
    tan(x) = sin(x) / cos(x)
    cot(x) = cos(x) / sin(x)
$$

which will place the formulas on separate lines:

This is useful when authoring cheat-sheets or problem solutions - this way you don’t have to fence every equation in the $ signs.

Technical note

This functionality is enabled by a custom rehype plugin and a custom remark plugin. You can read source code in /src/plugins/rehype-math/rehypeMath.ts and /src/plugins/remark-preserve-meta/remarkPreserverMeta.ts. In the compiled output, the math formulas will be represented as mjx-container elements with svg inside:

<mjx-container class="MathJax not-content" jax="SVG" overflow="overflow" display="true" width="full"><svg ...>...</svg></mjx-container>

Some of the meta defined after the $ fences will directly become attributes of the mjx-container. For example, justify = right meta will become an attribute of mjx-container. Other meta, like nl is used at the rehype processing stage. Passing attributes like justify to mjx-container helps style them properly. Styles are defined entirely by MathJax and Starlight.