# LaTeX symbol formatting

\int_{\mathbb R^D} \Delta S \cdot S \, dx
= -\int_{\mathbb R^D} \nabla S\cdot \nabla S\, dx
= \mean{(\nabla S)^2}


I want to write average symbol on $(\nabla S)^2$ but it is not workig. How can I write?

-
Do you mean \overline{..}? –  Werner Jun 12 '13 at 19:14
\mean{} this symbol –  Complex Guy Jun 12 '13 at 19:15
@Forhad If you need using \mean, \def\mean{\overline} should be a solution, but probably with an usage as in my answer. –  Przemysław Scherwentke Jun 12 '13 at 19:19
@Forhad Please, take a look at the Table 152, pp. 54 in tex.ac.uk/tex-archive/info/symbols/comprehensive/symbols-a4.pdf –  Papiro Jun 12 '13 at 19:45

You probably mean:

\int_{\mathbb R^D} \Delta S \cdot S \, dx
= -\int_{\mathbb R^D} \nabla S\cdot \nabla S\, dx
= \overline{(\nabla )^2 S}


or, as is suggested in comment

\documentclass{article}
\usepackage{amsmath,amssymb}
\begin{document}

\def\mean#1{\left< #1 \right>}

$\int_{\mathbb R^D} \Delta S \cdot S \, dx = -\int_{\mathbb R^D} \nabla S\cdot \nabla S\, dx = \mean{(\nabla S)^2}$

\end{document}


with the following result:

-
cant we do this by angle bracket? or by using \mean{} symbol? –  Complex Guy Jun 12 '13 at 19:20
@Forhad Are you thinking about \def\mean#1{\left< #1 \right>}? –  Przemysław Scherwentke Jun 12 '13 at 19:22
see the edit please –  Complex Guy Jun 12 '13 at 19:28