[OS X TeX] Size of braces and parentheses in split environment

[Axel E. Retif]

On  17 Aug, 2008, at 16:49, R Martinez wrote:

> All,
>
> The following display equation using a split environment produces  
> curly braces and parentheses of different sizes in each line of the  
> expression. I would like both lines to have braces and parentheses  
> that have the same size as those in the first line.
>
> Your help is appreciated.
>
> \begin{equation}
> \begin{split}
> 	K_z  &= \frac{1}{\left( \sigma_{x}^{2} + \sigma_{y}^{2}\right)^{2}}  
> \: \left(\mathcal{E} \left\{\left( X- \eta_x \right)^4 \right\} +  
> \mathcal{E} \left\{\left( Y- \eta_y \right)^4 \right\} \right. \\
> 	& \quad \quad +\left. 2\,\mathcal{E} \left\{\left( X- \eta_x  
> \right)^2 \left( Y- \eta_y \right)^2 \right\}  \right)
> \end{split}
> \end{equation}

I see them equal in both lines, but you will have to tell us which  
class, size and font package you're using, as there is a huge  
difference, for example, in the relative size of delimiters between  
article class at 12pt or 10pt:

\documentclass[12pt]{article} % <- change this to 10pt and see the  
difference
\usepackage{amsmath}
\usepackage[T1]{fontenc}
\begin{document}

Now load the Latin Modern fonts: \usepackage{lmodern} and you will not  
see that difference in the relative sizes of delimiters between 10pt  
and 12pt.

Now load TXfonts: \usepackage{txfonts}, and you'll see \left( X-  
\eta_x \right)^2 is not equal to \left( Y- \eta_y \right)^2.

I think the best for you is to set the sizes yourself: see page 56 of

http://www.ctan.org/get/info/lshort/english/lshort.pdf

and especially section 8 of

http://www.ctan.org/get/info/math/voss/mathmode/Mathmode.pdf

Best,

Axel