Math operator not magnified in beamer frame

Question

I would like to display a "big" formula in a beamer frame. If I test the \Large command this way

\documentclass[hyperref={colorlinks=true}]{beamer}

\usepackage[utf8]{inputenc}
\usepackage[italian]{babel}
\usepackage{lmodern}
\usepackage[T1]{fontenc}
\uselanguage{Italian}
\languagepath{Italian}
\usetheme{Warsaw}
\usepackage{pgf,tikz}
\usetikzlibrary{arrows}
\usetikzlibrary{quotes}
\usetikzlibrary{shapes.geometric,intersections,calc}
\usepackage{xcolor}
\usepackage{booktabs}
\usepackage{graphicx}

\begin{document}

\begin{frame}{Test}
\[
f(x)=\sum_{n=-\infty}^{+\infty}c_ne^{inx}
\]

\Large
\[
f(x)=\sum_{n=-\infty}^{+\infty}c_ne^{inx}
\]
\end{frame}
\end{document}

what I see is that the second formula is badly magnified: every symbol or letter is ok, but not the \sum operator, which remains small. What am I doing wrong?

This is what I see:

Answer 1

By using \scalebox or \resizebox from graphicx package, you can

\documentclass{beamer}
\usepackage{graphicx}% http;//ctan.org/pkg/graphicx
\begin{document}
\begin{frame}
\[
f(x)=\sum_{n=-\infty}^{+\infty}c_ne^{inx}
\]
\[
 \scalebox{2}{%
    $f(x)=\sum_{n=-\infty}^{+\infty}c_ne^{inx}$
}\]
\[
    \resizebox{3in}{0.5in}{%
        $f(x)=\sum_{n=-\infty}^{+\infty}c_ne^{inx}$
}\]
\end{frame}
\end{document}

here \scalebox{scale_factor}{content} and \resizebox{width}{height}{content} this gives