Make \rightrightarrows longer?

Question

Is there a way to make the \rightrightarrows symbol longer? I tried

f_n\overset{n\to\infty}{\rightrightarrows}f

but I am unhappy with the result:

I want something similar to this (using the extarrows package):

f_n\xlongrightarrow{n\to\infty}f

Answer 1

If you prefer there is another possibility using tikz-cd package to have you desidered output. The first example use the CM (computer modern font) and the Euler math fonts.

\documentclass[a4paper,12pt]{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{mathtools,amssymb}
\usepackage{eulervm}
\usepackage{tikz-cd}
%\renewcommand{\rmdefault}{pplx}
\begin{document}
First and second example in \textit{math-mode},
\[
        \begin{tikzcd}f_n \arrow[r, "n\to\infty"] &[2em] f \end{tikzcd}\]
\[       \begin{tikzcd}f_n \arrow[r, "n\to\infty"] &[.5em] f\end{tikzcd} 
\]
Third example inline mathmode $\begin{tikzcd} f_n \arrow[r, "n\to\infty"] &[.2em] f\end{tikzcd}$  if you want, after, to write a comment.
\end{document}

With the second example you have, the Palatino fonts for the text (\renewcommand{\rmdefault}{pplx}) that they adapt with it using Euler math fonts.

\documentclass[a4paper,12pt]{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{mathtools,amssymb}
\usepackage{eulervm}
\usepackage{tikz-cd}
\renewcommand{\rmdefault}{pplx}
\begin{document}
First and second example in \textit{math-mode},
\[
        \begin{tikzcd}f_n \arrow[r, "n\to\infty"] &[2em] f \end{tikzcd}\]
\[       \begin{tikzcd}f_n \arrow[r, "n\to\infty"] &[.5em] f\end{tikzcd} 
\]
Third example inline mathmode $\begin{tikzcd} f_n \arrow[r, "n\to\infty"] &[.2em] f\end{tikzcd}$  if you want, after, to write a comment.
\end{document}