[OS X TeX] Typesetting equation w/o fractions appearing in smaller fontsize

[Morten Høgholm]

On Fri, Apr 17, 2009 at 2:43 PM, Franck Pastor wrote:
>
> Le 17 avr. 09 à 14:06, Michael Kubovy a écrit :
>> \usepackage{amsmath}
>>
>> \begin{document}
>>
>> \[
>> \mathcal{B}_{s}(x) =
>> \begin{cases}
>> \frac{r \log_{2} \frac{r}{(r + 1)} } {\log_{2} \frac{1}{(r + 1)} } &
>> \text{if $x_{i}^{(2)} = y_{i}^{(2)}$;}\\
>> \frac{\log_{2} \frac{1}{(r + 1)} } {r \log_{2} \frac{r}{(r + 1)} } &
>> \text{if $x_{i}^{(2)} \neq y_{i}^{(2)}$.}
>> \end{cases}
>> \]
[...]
>> How do I make all font sizes the same?
>
>
> You can use \dfrac (from the amsmath package) instead of \frac.

the mathtools package provides dcases and dcases* environments for
exactly this situation with the following syntax:

\begin{dcases} math_column & math_column \end{dcases}
\begin{dcases*} math_column & text_column \end{dcases*}

Just load mathtools instead of amsmath: it loads amsmath itself.
-- 
Morten