Display math and tabular

I'm pretty new to latex and having some trouble. I have multiple math formulas which I'd like to organize on the page. i used:

\begin{tabular}{p{6cm}p{6cm}}
$...$ & $...$\\
\end{tabular}


for this. The problem is the following one: the first formula has different indent depending on its own length (the second one is always on the same place).I guess it's the centering of the displaymath? Is there a way to have the display mode and always the same indent, or should I use another environment?

• Welcome to TeX.SE. You can use $\displaystyle ...$. Also, while code snippets are useful in explanations, it is always best to compose a fully compilable MWE that illustrates the problem including the \documentclass and the appropriate packages so that those trying to help don't have to recreate it. – Peter Grill Jun 13 '14 at 21:02
• @PeterGrill Can you make than answer. – Andrew Swann Dec 29 '14 at 9:15

The problem is with the use of display math mode. Instead you could use inline math and specify \displaystyle:

If your tables only have math content then I would suggest using an array as in the last example above. Although, I am not sure why the spacing is slightly different.

Notes:

• I am not advocating the user of vertical rules. They were added just to show where the content is with respect to the borders.

Code:

\documentclass{article}
\usepackage{amsmath}
\usepackage{array}

\begin{document}
\noindent
Using \verb|display math mode|

\noindent
\begin{tabular}{|p{6cm}|p{6cm}|}
$y =\sum_{i=0}^{n} i^2$ & $y =\sum_{i=0}^{n} i^2$ \\
\end{tabular}

\medskip\noindent
Using \verb|\displaystyle|

\noindent
\begin{tabular}{|p{6cm}|p{6cm}|}
$\displaystyle y =\sum_{i=0}^{n} i^2$ & $\displaystyle y =\sum_{i=0}^{n} i^2$ \\
\end{tabular}

\medskip\noindent
Using \verb|\displaystyle| with an \verb|array|:

\noindent
$\begin{array}{|>{$\displaystyle}p{6cm\relax}<{$}|>{$\displaystyle}p{6cm}<{$}|} y =\sum_{i=0}^{n} i^2 & \displaystyle y =\sum_{i=0}^{n} i^2 \\ \end{array}$

\end{document}


For a fixed-indentation in your tabular, insert an \hspace*{<len>} or \quad/\qquad:

\documentclass{article}
\usepackage{array}
\newcolumntype{M}[1]{>{$\displaystyle\qquad}p{#1}<{$}}

\begin{document}

\noindent
\begin{tabular}{|M{6cm}|M{6cm}|}
y =\sum_{i=0}^{n} i^2 & \displaystyle y =\sum_{i=0}^{n} i^2 \\
y =\sum_{i=0}^{n} (i+1)^2 & \displaystyle y =\sum_{i=0}^{n} i^2 \\
y =\sum_{i=0}^{n} \bigl(i^2+i+1\bigr)^2 & \displaystyle y =\sum_{i=0}^{n} i^2 \\
\end{tabular}

\end{document}