31

Quick question. When I type $e^{\frac{1}{2x}}$ it makes the fraction very small and hard to read. However when I type $e^{\displaystyle\frac{1}{2x}}$ it makes the fraction way to big. I guess in either case they do not look good to me. Is there a nice way to make fractions in powers look good?

30

You can also use the xfrac package which provides \sfrac which works in text and math mode:

enter image description here

Note:

Code:

\documentclass{article}
\usepackage{xfrac}

\begin{document}
Works in text mode \sfrac{1}{2} and in math mode $\sfrac{1}{2}$.

In exponents: $e^{\sfrac{1}{2}}$
\end{document}
19

Your question was:

While in text mode (aka inline math mode), how does one make fractions in powers look good?

A very important objective in fine typography is to keep the "color" -- really, the "average grayness" -- of paragraphs uniform within a page and across pages. One important aspect of "color" is the line spacing and, in particular, its uniformity: If interline spacing varies noticeably within a paragraph and across paragraphs, "color" is jeopardized and the document is going to look awful, at least from a typographic standpoint.

Unless you have something like doublespacing in place (and have therefore ruined the look of the paragraph anyway), having math terms with fractional exponents inside running text requires TeX to insert a considerable amount of extra vertical whitespace relative to the preceding line, ruining the paragraph's color. That's a good reason for trying to avoid using any terms in subscript and superscript positions that force TeX to insert extra interline spacing, right? In the TeXbook, Knuth recommends using inline-style fractional expressions, e.g., $1/2$ instead of \frac{1}{2}, for just this situation.

As you've noted, writing $e^{\frac{1}{2x}}$ renders the material in the numerator and denominator in scriptscriptstyle (50% linear reduction from textstyle), which makes it potentially hard to decipher. Some potential fixes:

  • Using inline fractional math notation, i.e., writing $e^{1/2x}$, renders the material in the exponent in scriptstyle (30% linear reduction from textstyle), which should be no problem for legibility.

  • The \nicefrac macro (provided by the nicefrac package), when used in an exponent, makes the fractional term look a lot less cramped than if \frac were used; however, it also renders the numerator and denominator in scriptscriptstyle, re-raising the issue of basic legibility.

  • If the term in the exponent is too complicated to be displayed easily in superscript position, consider typing $\exp(\sfrac{1}{2x})$. (The \nicefrac and \sfrac macros typeset their argument very similarly, by the way.)

In the following screenshot, the \dfrac solution is shown mostly to illustrate what should not be done under any circumstance. My personal preference would be for either the third or the fifth solution.

enter image description here

\documentclass{article}
\usepackage{xfrac}    % for \xfrac macro
\usepackage{nicefrac} % for \nicefrac macro
\usepackage{amsmath}  % for \dfrac macro
\newcommand{\e}{\mathrm{e}}

\begin{document}
some words $\e^{\frac{1}{2x}}$ $\e^{\dfrac{1}{2x}}$ $\e^{1/2x}$ 
$\e^{\nicefrac{1}{2x}}$ $\exp(\sfrac{1}{2x})$ some more words
\end{document}
13

Here are the variants to choose

\documentclass{article}
\usepackage[nice]{nicefrac}
\begin{document}
  $e^{1/2}$ $e^{(1/2)}$ $e^{0.5}$

  With \verb|nicefrac|

    $e^{\nicefrac{1}{2}}$

\end{document}

enter image description here

With ugly option to nicefrac:

\documentclass{article}
\usepackage[ugly]{nicefrac}
\begin{document}
  With \verb|nicefrac|

    $e^{\nicefrac{1}{2}}$

\end{document}

enter image description here

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