Resize Fractions

Question

I am using the \dfrac command to write proofs, but i get them so small. How can I adjust the size?

here is my MWE:

\documentclass{article}
\usepackage{proof}
\setlength{\inferLineSkip}{6pt}
\begin{document}
\begin{center}
    $ \begin{array}{c}
      \dfrac{A}{C}\ \rlap{\textbf{R1}}  
 \end{array}$
\end{center}
\end{document}

And i get this result:

Could you help me please?

Answer 1

If you want to use the proof package, adopt its syntax:

\documentclass{article}
\usepackage{proof}

\setlength{\inferLineSkip}{6pt}

\begin{document}

\[
\infer[\textbf{R1}]{C}{A}
\]

\end{document}

Answer 2

It is an optical illusion that R is bigger than A and C. However, you can use a larger font, which, of course, doesn't really make sense:

\documentclass{article}
\usepackage{amsmath}
\newcommand\bfrac[3]{{\large\ensuremath{\dfrac{#1}{#2}}~\textbf{#3}}}
\begin{document}

\bfrac{A}{C}{R1} $\dfrac{A}{C}$

\end{document}