Formula reference
Every way to write a formula, chemistry and physics notation, your own commands, and equation numbering.
This page lists everything the note editor's formulas support. For the basics, start with Maths and formulas.
How formulas are written
Formulas are rendered by KaTeX. Every command KaTeX supports works, except those that add links, images or HTML, such as \href and \includegraphics, which show in red.
| Where | Type | Becomes |
|---|---|---|
| At the start of a line | $$x^2$$, $$$x^2$$$ or \[x^2\] | a block |
| Inside a line | $$x^2$$ or \(x^2\) | a formula in the line |
| Inside a line | $x^2$, followed by a space or punctuation | a formula in the line |
| Anywhere | /math | a block, through the dialog |
In imported Markdown, $...$ is a formula in the line. $$...$$ is a block when it has a line to itself or sits between two $$ lines, and a formula in the line anywhere else.
Chemistry
Chemistry comes from mhchem: \ce{H2O}, \ce{CO2 + C -> 2CO}, \ce{SO4^2-} and quantities such as \pu{123 kJ//mol}.
Physics
Physics notation comes from part of the LaTeX physics package:
- derivatives:
\dv{f}{x},\dv[2]{y}{t},\pdv{f}{x},\pdv{f}{x}{y}, and\dd{x}for the d at the end of an integral - brackets that grow with what they hold:
\abs{x},\norm{v},\qty(\frac{a}{b}),\qty[x]and\qty|x|.\abs*{x}and\norm*{v}keep them at text size. - vectors:
\vb{F}in bold,\va{r}with an arrow,\vu{n}with a hat,\vdot,\cross,\grad,\divergence,\curland\laplacian - quantum mechanics:
\bra{\psi},\ket{\phi},\braket{\psi}{\phi},\expval{H},\mel{n}{H}{m}and\comm{A}{B} - also
\eval{x^2}_0^1,\order{x^2},\mqty(a & b \\ c & d)for a matrix, and\Tr,\rank,\erfand\Res
\div stays division, as in plain LaTeX.
Your own commands
\newcommand, \renewcommand, \def and \DeclareMathOperator all work. A command defined in a formula applies to that formula and to every formula after it in the same note, as in a LaTeX document, so \newcommand{\R}{\mathbb{R}} near the top serves the whole note.
- Moving or deleting the definition changes the formulas below it.
- Commands never carry over to another note.
- A formula on a study set card or in a test question stands alone: a command it defines works only inside it.
Numbered equations
Formulas in equation, align, gather and alignat are numbered (1), (2), (3) down the note. The starred forms, such as align*, are not.
- Give a line
\label{name}, and\eqref{name}in any formula shows its number, which follows when equations above it are added or removed. \tag{A}gives a line its own label instead of a number, and\nonumberleaves a line out.- A label no formula has shows as
(??).
Copying, exporting and the AI still see the LaTeX as you wrote it, \label and \eqref included.
Not supported yet
multline, \cancelto, siunitx (\SI) and drawing packages such as TikZ. A command KaTeX doesn't know shows in red.