Bigger equation in text-mode math

Question

I want to write a "big" equation, not in display-math mode -- as given by the equation environment -- but in inline-math mode, say

$E=mc^2$

How can I enlarge it?

Answer 1

Will one of \large, \Large, \LARGE, \huge, or \Huge do? Observe that because these commands are text-mode commands, they must be executed before entering math mode.

\documentclass{article}
\usepackage{xcolor}
\begin{document}
\obeylines
{\tiny $E=mc^2$}
{\scriptsize $E=mc^2$}
{\footnotesize $E=mc^2$}
{\small $E=mc^2$}
{\color{red} $E=mc^2$ --- \texttt{\textbackslash normalsize}} % \normalsize is the default
{\large $E=mc^2$}
{\Large $E=mc^2$}
{\LARGE $E=mc^2$}
{\huge $E=mc^2$}
{\Huge $E=mc^2$}
\end{document}

Note the use of the curly braces to limit the scope of the size-setting switches.

Answer 2

Welcome to TeX.SE! There are different solutions given in the comment section but here's another one that could be less verbose and customizable.

\documentclass{article}
\usepackage{graphicx}% \scalebox

\newcommand{\enlargeMath}[1]{\scalebox{2}{#1}}

\begin{document}
    \noindent Normal font: $X_2^2$\\[1ex]
    enlarged font: \scalebox{2}{$X_2^2$}\\[1ex]
    % or using the \enlargeMath command that we 
    % defined to eliminate the scale factor.
    \enlargeMath{$X_2^2$}
\end{document}