How can I make the underbraced bigger?

I have to kind of underbraces:

\begin{equation}\label{eq:romberg2}
M=N\left(\frac{h}{2}\right)+\underbrace{K_{1}\frac{h}{2}+K_{2}\frac{h^{2}}{4}+K_{3}\frac{h^{3}}{8}+\hdots}_{\text{\normalsize{Error}}}
\end{equation}


which works well (except from the not-centered "Error"), and:

\begin{equation}
M=\underbrace{N\left(\frac{h}{2}\right)+\left[N\left(\frac{h}{2}\right)-N(h)\right]}_{N_{2}(h)}+K_{2}\left(\frac{h^{2}}{2}-h^{2}\right)+K_{3}\left(\frac{h^{3}}{4}-h^{3}\right)+\hdots
\end{equation}


which makes my $N_{2}(h)$ small. I have tried using \normalsize, \large, \big, etc. inside the underbrace but didn´t make any difference.

Do you know how to make the $N_{2}(h)$ bigger? and how can I center the underbraced "Error" from the first equation?

Thank you

• Welcome to TeX.SE!. You could use \displaystyle: \begin{equation} M=\underbrace{N\left(\frac{h}{2}\right)+\left[N\left(\frac{h}{2}\right)-N(h)\right]}_{\displaystyle N_{2}(h)}+K_{2}\left(\frac{h^{2}}{2}-h^{2}\right)+K_{3}\left(\frac{h^{3}}{4}-h^{3}\right)+\hdots \end{equation} – marmot Feb 16 at 12:04
• You can also load the graphicx package and place the $N_2(h)$ in a \scalebox - see tex.stackexchange.com/a/31417/172926 – Pippip19 Feb 16 at 12:44
• I think the “Error” text is centered, but it looks off center. That is a visual illusion, I think. You could try adding a space, as in \text{\normalsize{Error }}, to shove it left a bit. Or a suitable \hspace if the regular space is too big. (By the way, the inner pair of curly braces are not needed. I left them in to make it clear not to confuse you with yet another space that will be gobbled up.) – Harald Hanche-Olsen Feb 17 at 13:18

Use \textstyle:

\documentclass{article}
\usepackage{amsmath}

\begin{document}

\begin{equation}
M=N\left(\frac{h}{2}\right)+
{\underbrace{
K_{1}\frac{h}{2}+K_{2}\frac{h^{2}}{4}+K_{3}\frac{h^{3}}{8}+\dotsb
}_{\textstyle\text{Error}}}
\end{equation}

\begin{equation}
M={\underbrace{
N\left(\frac{h}{2}\right)+\left[N\left(\frac{h}{2}\right)-N(h)\right]
}_{\textstyle N_{2}(h)}}+
K_{2}\left(\frac{h^{2}}{2}-h^{2}\right)+K_{3}\left(\frac{h^{3}}{4}-h^{3}\right)+
\dotsb
\end{equation}

\end{document} Remember the braces around the \underbrace construction, or the spacing around it might be wrong.

I'd remark that \hdots is not the right command in that case and \dotsb is better.