# How to fix an ugly fraction with exponent?

Here's a simple fraction that I find extremely ugly. What could I do to get a better looking result (without using a negative exponent) ?

\documentclass[11pt,letterpaper,twoside]{book}
\usepackage[T1]{fontenc}
\usepackage{lmodern}
\usepackage{microtype}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{mathtools}
\usepackage{tensor}

\begin{document}

TEST
$$a(t) = \frac{g}{\bigl(1 + (g t / c)^2 \bigr)^{\frac{3}{2}}}.$$

\end{document}


Preview:

Of course, I could use 3/2 instead of \frac{3}{2}, but I believe the result is worst. I tried \displaystyle and \textstyle for the bottom part of the fraction, but the exponent is still creating the trouble. So what would you do to get a better looking fraction with its pesky exponent, without writing everything at the numerator with a negative exponent?

• There's no way to remove that white space, because the exponent is higher than the parenthesis: this is exactly why you should use 3/2. Lowering the exponent would be much worse. – egreg Mar 1 at 17:55
• @SandyG, the second line of my question is excluding this option. – Cham Mar 12 at 1:16
• Sorry. Didn't see that. – Sandy G Mar 12 at 2:24
• Problem solved? – Dr. Manuel Kuehner May 17 at 1:14

A couple of suggestions

\documentclass[11pt,letterpaper,twoside]{book}
\usepackage[T1]{fontenc}
\usepackage{lmodern}
\usepackage{microtype}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{mathtools}
\usepackage{tensor}

\begin{document}

TEST
$$a(t) = \frac{g}{\bigl(1 + (g t / c)^2 \bigr)^{\frac{3}{2}}}.$$

TEST2
$$a(t) = \frac{g}{(1 + (g t / c)^2)^{\frac{3}{2}}}.$$

TEST3
$$a(t) = \frac{g}{(1 + (g t / c)^2)^{\scriptscriptstyle\frac{3}{2}}}.$$

\end{document}

• I just found that smashing the "big" parenthesis helps a lot. The double same-sized parenthesis isn't good looking, in my opinion. You could add the smashing option as a TEST4. – Cham Mar 1 at 18:17
• @Cham I wondered about smash, but I don't think I'd ever use big delimiters here irrespective of the fraction and superscript. – David Carlisle Mar 1 at 18:49

Perhaps this hack with bigstrut will befit you?

\documentclass[11pt,letterpaper,twoside]{book}
\usepackage[T1]{fontenc}
\usepackage{lmodern}
\usepackage{microtype}
\usepackage{amsfonts}
\usepackage{mathtools}
\usepackage{bigstrut}
\newcommand{\mybigstrut}[1] {{\setlength{\bigstrutjot}{#1}\bigstrut[b]}}

\begin{document}

TEST

$$a(t) = \frac{g_{\mybigstrut{5pt}}}{\bigl(1 + (g t / c)^2 \bigr)^{\!\frac{3}{2}}}.$$

\end{document}


One approach is to move the exponent out from the denominator and reposition it accordingly. I used \! to move it left a bit, and then either raisebox to lower it by trial and error or genfrac to have the exponent in a phantom denominator.

\documentclass[11pt]{amsart}

\begin{document}

\begin{align*}
\text{original: }&a(t) = \frac{g}{\bigl(1 + (g t / c)^2 \bigr)^{\frac{3}{2}}}.\\
\text{raisebox: }&a(t) = \frac{g}{\bigl(1 + (g t / c)^2 \bigr)}\!\raisebox{-.5ex}{$\scriptstyle\frac{3}{2}$}.\\
\text{genfrac: }&a(t) = \frac{g}{\bigl(1 + (g t / c)^2 \bigr)}\!\genfrac{}{}{0pt}{0}{}{{}^{\frac{3}{2}}}.
\end{align*}

\end{document}