# Math Help - Big Fractions and Big Arrays

1. ## Big Fractions and Big Arrays

Hello friends,

This is a problem I've been facing for a while. Suppose that I wanted to write $\displaystyle \frac{\prod\text{stuff}}{\prod\text{more stuff}}$ but I wanted to force the product to be normal displaystyle size. Similarly, suppose that I had a matrix whose entries were sums/products/integrals and I wanted those to be normal displaystyle size, can I do this? I know the matrix/fraction would be huge, but that isn't an issue.

2. Originally Posted by Drexel28
Hello friends,

This is a problem I've been facing for a while. Suppose that I wanted to write $\displaystyle \frac{\prod\text{stuff}}{\prod\text{more stuff}}$ but I wanted to force the product to be normal displaystyle size. Similarly, suppose that I had a matrix whose entries were sums/products/integrals and I wanted those to be normal displaystyle size, can I do this? I know the matrix/fraction would be huge, but that isn't an issue.
Put the \displaystyle command in each array item (fraction component, matrix entry, or whatever):
$\frac{\displaystyle \prod\text{stuff}}{\displaystyle \prod\text{more stuff}}$

3. Originally Posted by Opalg
Put the \displaystyle command in each array item (fraction component, matrix entry, or whatever):
$\frac{\displaystyle \prod\text{stuff}}{\displaystyle \prod\text{more stuff}}$
You know, I never would have guessed to do that. I've LaTeXed a lot, and I would have guessed that that would read error since it was a 'precursor' command--or so I thought. Thanks Opalg!

4. Originally Posted by Drexel28
I would have guessed that that would read error since it was a 'precursor' command--or so I thought.
The default TeX style for array and similar items is that they are one level lower than the ambient style. So if you are working in displaystyle then these items will be in textstyle, if you are in textstyle then they will be in scriptstyle, and if you are in scriptstyle then they will be in scriptscriptstyle. If you want to override those settings then you have to do so explicitly for each separate item.

If that gets too tedious then you can abbreviate it by using a macro. After \def\ds{\displaystyle}, you only need to write \ds each time, rather than \displaystyle.