Big double integral sign

Question

I'm trying to make a double integral, but, somewhy, the sign appears small compared to regular integral signs, does anybody knows why? And how do I solve this? I am using the 'equation' environment

Answer 1

Package amsmath

\documentclass{article}
\usepackage{amsmath}

\begin{document}
\[
  \int \iint
\]
\end{document}

The size is the same, maybe, you want to use this.

Package wasysym

\documentclass{article}
\usepackage{wasysym}

\begin{document}
\[
  \int \iint
\]
\end{document}

Package wasysym does not provide the larger more slanted form. However, the standard integral can be redefined to match the double integral:

\documentclass{article}
\usepackage[integrals]{wasysym}

\begin{document}
\[
  \int \iint
\]
\end{document}

Other

There are lots of other packages, which provide the double integral, but most of them also change the appearance of other symbols (mathabx, txfonts, ...). See The Comprehensive LaTeX Symbol List.