# Resizing the sum operator [duplicate]

The following simple expression produces a sum operator as in (1). But I want it to be bigger like in (2), of course, without altering the size of inner braces. Any suggestion?

\documentclass[a4,12pt]{article}
\begin{document}
$$\sum_{i=1}^{N_P}\biggl(X^{(i)}-Y^{(i)}\biggr)^2$$
\end{document}


## marked as duplicate by Mico, yo', Manuel, user31729, egreg fonts StackExchange.ready(function() { if (StackExchange.options.isMobile) return; $('.dupe-hammer-message-hover:not(.hover-bound)').each(function() { var$hover = $(this).addClass('hover-bound'),$msg = $hover.siblings('.dupe-hammer-message');$hover.hover( function() { $hover.showInfoMessage('', { messageElement:$msg.clone().show(), transient: false, position: { my: 'bottom left', at: 'top center', offsetTop: -7 }, dismissable: false, relativeToBody: true }); }, function() { StackExchange.helpers.removeMessages(); } ); }); }); Nov 7 '14 at 18:17

• Please have a look on tex.stackexchange.com/questions/503/why-is-preferable-to ;-) – user31729 Nov 7 '14 at 17:06
• There is no reason for using \bigg in the first expression; if you use simple ( and ), the size of the summation symbol is just right. And there's no reason for increasing the size of \sum under any circumstance, in my opinion. – egreg Nov 7 '14 at 17:07
• @egreg well, I actually need it bigger – Tnoor Nov 7 '14 at 17:42
• @Tnoor No, you want it bigger. You didn't give any reason why it has to be bigger. The problem is that there's no such reason, as far as I know. – yo' Nov 7 '14 at 17:47
• @Tnoor The fact is "why", because when I copy edit articles and other works done by people who think they "know the things" and they actually do not, it is very painful, takes a lot of time, and costs money to the university which I work for. That's one of the reasons why many people here want everybody to use LaTeX to do good typography, and not to defile their documents. – yo' Nov 7 '14 at 18:03

\documentclass{article}
\usepackage{graphicx}
\newcommand*{\Scale}[2][4]{\scalebox{#1}{$#2$}}%
\newcommand*{\Resize}[2]{\resizebox{#1}{!}{$#2$}}%
\begin{document}

$\sum_{i=1}^{N_P}\biggl(X^{(i)}-Y^{(i)}\biggr)^2$

$\mathop{\Scale[2]{\sum}}_{i=1}^{N_P}\biggl(X^{(i)}-Y^{(i)}\biggr)^2$

\end{document}


Compile with LuaLaTeX (or XeLaTeX).

\documentclass{scrartcl}
\usepackage{unicode-math}
\setmathfont{Cambria Math}
\begin{document}
$\sum_{i=1}^{N_P} \bigl(X^{(i)} - Y^{(i)}\bigr)^2$
\end{document}