Changing the \sum symbol in fraction

Question

I would like my \sum symbol to appear like on the right side of the equation (n on top and i on the bottom) rather than be on the side, however when I use \frac, the shape of \sum changes as I tried to display in the image. How can I force the sum symbols in the fraction to appear like the on the right?

\begin{align}
{\color{dca}\sigma(a_k,b_k)} = \frac{\sum_{i=1}^n (a_ki - \overline{a_k})(b_ki - \overline{b_k})}{\sqrt{\sum_{i=1}^n (a_ki - \overline{a_k})^2(b_ki - \overline{b_k})^2}} 
\end{align}

Your code does not match the output, but only a part of it. Also, please always provide a full minimal working example (MWE). You can write probably use \frac{\sum\limits_{i=1}^n}{x}. — Jasper Habicht, Jul 04 '22 at 13:10

score 4 · Accepted Answer · answered Jul 04 '22 at 13:15

As I don't know what \color{dca} is, I replaced it with IndianRed (from svgnames). Here is a simple solution:

    \documentclass{article}
    \usepackage[svgnames]{xcolor}
    \usepackage{amsmath}
\begin{document}

\begin{align}
{\color{IndianRed}\sigma(a_k,b_k)} = \frac{\sum\limits_{i=1}^n (a_ki - \overline{a_k})(b_ki - \overline{b_k})}{\sqrt{\sum\limits_{i=1}^n (a_ki - \overline{a_k})^2(b_ki - \overline{b_k})^2}}
\end{align}

\end{document}

Changing the \sum symbol in fraction

1 Answers1