Dot in LaTeX (\dot{x})

Where it is used

Adds a single dot above a variable, Newton's notation for the first time derivative.

In mechanics and dynamical systems \dot{x} means dx/dt, so equations like \dot{x} = Ax or the Lagrangian L(q, \dot{q}, t) are written compactly. Physicists also use it for rates such as \dot{m} for mass flow. The dot is a math accent and works over Greek letters too: \dot{\theta}. Do not confuse it with \cdot (a centered multiplication dot) or with the text-mode accent \.{z} used in Polish words. For the second derivative use \ddot{x} rather than stacking two \dot commands, which misaligns the dots.

Also listed under: Calculus & Analysis

Minimal compilable example

Paste this into an empty .tex file and compile it with pdfLaTeX, XeLaTeX or LuaLaTeX.

\documentclass{article}
\begin{document}
Dot: $\dot{x}$

\[ \dot{x}(t) = A x(t) + B u(t) \]
\end{document}

Related symbols

• Double Dot\ddot{x}
• Wide Tilde\widetilde{xyz}
• Triple Dot\dddot{x}
• Tilde\tilde{x}
• Bar\bar{x}
• Wide Hat\widehat{xyz}

Frequently asked questions

How do I write Dot in LaTeX?

Type \dot{x} in math mode, for example $\dot{x}(t) = A x(t) + B u(t)$. It works in plain LaTeX without loading any package.

Which package do I need for \dot{x}?

None. \dot{x} is part of standard LaTeX, so it compiles with nothing in the preamble but the document class.

Can I use \dot{x} in text mode, or only in math mode?

Only in math mode. Outside $...$ LaTeX stops with "Missing $ inserted", so write $\dot{x}$ in running text.