[Tex/LaTex] Make numerator and denominator terms of \frac bigger

Question

Is there a way to make \frac{}{} bigger? By default looks like all equations keep the same size. That means if I write x=\frac{a}{b} x has the right size, while frac is a little bit smaller. I want that x, numerator and denominator keep the same size.

Answer 1

I assume your document is in inline math mode when the fraction occurs.

• While in inline math mode, the numerator and denominator of \frac are set in \scriptstyle by default. Script-size letters and symbols are about 30% (linearly) smaller than in text size.

• To force TeX to typeset the numerator and denominator terms in \textstyle, either prefix the \displaystyle directive to \frac or -- if the amsmath package is loaded -- write \dfrac.

• If you want to typeset the numerator and denominator terms in \displaystyle (which may be necessary if you have "large" math symbols such as \sum and \prod), it's best to set up a dedicated macro called, say, \ddfrac to perform the job.

\documentclass{article}
\usepackage{amsmath} % for \dfrac macro
\newcommand\ddfrac[2]{{\displaystyle\frac{\displaystyle #1}{\displaystyle #2}}}
\newcommand\numer{\sigma_{\mathit{tot}}}
\newcommand\denom{\omega\epsilon_0}
\begin{document}  
$\epsilon''=\frac{\numer}{\denom}$,              %\frac
$\epsilon''=\displaystyle\frac{\numer}{\denom}$, %\displaystyle\frac
$\epsilon''=\dfrac{\numer}{\denom}$,             %\dfrac
$\epsilon''=\ddfrac{\numer}{\denom}$             %\ddfrac
\end{document}