Displaystyle Package?

Question

I am curious to know if there is a display style package, or something that would produce the same effect. You see, I get tired of constantly having to type \displaystyle, and making sure that it is in every place that it should be.

Is there some package that will "automatically" display style all of math symbols?

Answer 1

Note that I do not actually recommend you do the following. But, since you ask: You can force TeX/LaTeX to issue the directive \displaystyle automatically whenever you initiate inline-math mode -- via either an opening-$ or a \( instruction -- by inserting the following command in your document's preamble:

\everymath{\displaystyle}

Again, I do not recommend you take this route. There are excellent typographic reasons for not using large summation, product, and integral symbols while in inline-math mode. Likewise, it's almost invariably a bad idea to typeset display-style fraction constructs while in inline math mode.

For much more information on this matter, I suggest you take a look at the posting Show inline math as if it were display math.

I can think of only one exception to the broad stricture against the automatic use of \displaystyle: In beamer-class documents, it is quite important not to let the math symbols become too small. One way of achieving this is to use \displaystyle throughout. Even for beamer documents, though, providing the instruction \everymath{\displaystyle} may be too much of a good thing.

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Addendum, prompted by a follow-up comment by the OP: To revert back to "text style" while in inline math mode, just issue the command \textstyle. The following MWE illustrates the look of various math objects if \displaystyle and \textstyle are in effect:

\documentclass{article}
\everymath{\displaystyle} % automatically use display style while in inline math mode
\begin{document}
$\sum \quad \prod \quad \int \quad \frac{abc}{xyz}$

$\textstyle\sum \quad \prod \quad \int \quad \frac{abc}{xyz}$
\end{document}