math-modephysics
The physics package defines commands such as \grad, \div and \curl so that any subsequent delimiters are automatically resized (see MWE below). However, they also use a bold nabla. I would like to redefine the commands such that the automatic resizing is preserved but using a regular nabla. Is there any way this is possible?
\documentclass{article}
\usepackage{physics}
\begin{document}
\[ \nabla(\frac{a}{b}) \]
\[ \grad(\frac{a}{b}) \]
\end{document}
\dot is a command requiring a parameter, to set a dot above some character, to indicate the time derivative. The multiplication dot can be obtained using \cdot!
Another error were the missing \ (but without complaining) just before abs.
Please don't use the outdated $$....$$ syntax -- use \[....\] instead.
\documentclass{book}
\usepackage{physics}
\begin{document}
\LARGE
\[ \va{A} \cdot \va{B} = \abs{A}\cdot \abs{B}\cdot \cos{\theta}\]
\end{document}
A solution using mathtools:
\documentclass{revtex4-1}
\usepackage{mathtools}
\DeclarePairedDelimiter\abs{\lvert}{\rvert}
\DeclarePairedDelimiterX\phys[3]{\langle}{\rangle}{#1 \delimsize\vert\mathopen{} #2 \delimsize\vert\mathopen{} #3}
\newcommand*\Vector[1]{\boldsymbol{#1}}
\begin{document}
\begin{equation}
\abs*{\prescript{}{u}{\phys*{\nu,\Vector{0}}{\Vector{k} \cdot \Vector{p}}{\nu',\Vector{0}}}_{u}}^{2}
\end{equation}
\end{document}
For your particular problem, the \prescript macro is the key.
Best Answer