LaTeX Math Modes: \textstyle, \displaystyle, \scriptstyle, and \scriptscriptstyle
May. 09, 2024
For equations in LaTeX mathematical environments, there are four commands to specified their style1:
\textstyle(default for in-line math style): apply the style used for mathematics typeset in paragraphs.\displaystyle(default for display math style): apply the style used for mathematics typeset on lines by themselves.\scriptstyle: apply the style used for subscripts or superscripts.\scriptscriptstyle: apply the style used for second-order subscripts or superscripts.
Here is an example to show the differences between them.
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\documentclass[a4paper,11pt]{article}
\usepackage[margin=1in]{geometry}
\usepackage[x11names]{xcolor}
\pagecolor{AntiqueWhite1}
\usepackage{lipsum}
\usepackage{amsmath}
\newcommand{\myequation}{f(n) = \sum_{i=0}^n \frac1n,\ g(x) = \int_0^1\frac1x\mathrm{d}x}
\newcommand{\mytext}{\lipsum[1][1-3]}
\begin{document}
\section{Inline equations (in-text equations)}
\verb|\textstyle| (\textcolor{red}{default}): $\textstyle \myequation$, (\mytext)
\verb|\displaystyle|: $\displaystyle \myequation$, (\mytext)
\verb|\scriptstyle|: $\scriptstyle \myequation$, (\mytext)
\verb|\scriptscriptstyle|: $\scriptscriptstyle \myequation$, (\mytext)
\section{Display equations}
\verb|\textstyle|:
(\mytext)
\begin{equation}
\textstyle \myequation
\end{equation}
\mytext
\verb|\displaystyle| (\textcolor{red}{default}):
(\mytext)
\begin{equation}
\displaystyle \myequation
\end{equation}
\mytext
\verb|\scriptstyle|:
(\mytext)
\begin{equation}
\scriptstyle \myequation
\end{equation}
\mytext
\verb|\scriptscriptstyle|:
(\mytext)
\begin{equation}
\scriptscriptstyle \myequation
\end{equation}
\mytext
\end{document}
Before, I liked using \dfrac command to generate fraction sign. This is because that once I discovered the effect of \dfrac is better than \frac when I was a totally beginner for LaTeX, and kept this habit since then although I forget the specific reason why. But right now I find aforementioned commands don’t affect the parts generated by \dfrac.
For example, similarly for the above case, but at this time I replace \frac with \dfrac:
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% ...
\newcommand{\myequation}{f(n) = \sum_{i=0}^n \dfrac1n,\ g(x) = \int_0^1\dfrac1x\mathrm{d}x}
% ...
then we have:
So, I search the reason on the Internet, and find it2:
\dfracmeans that the fraction is set in displaystyle\tfracmeans that the fraction is set in textstyle- with
\frac: the actual context implies the decision above.
Interesting!
References