latex integral mit grenzen / latex integral limits

\documentclass{article}
\begin{document}
 $\int_{-\infty}^{\infty} x \ dx$ vs.
 $\int\limits_{-\infty}^{\infty} x \ dx$ 
\end{document}

latex integral dx

\documentclass{article}
\begin{document}
 $\int x dx$ vs. $\int x \ dx$ 
\end{document}

latex integral größer

\documentclass{article}
\usepackage{bigints}
\begin{document}
 $\int x$ $\bigintssss x$ $\bigintsss x$ 
 $\bigintss x$ $\bigints x$ $\bigint x$ 
\end{document}

latex integralzeichen

\documentclass{article}
\begin{document}
 $\smallint x$ vs. $\int x$ 
\end{document}