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

\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}– Feb 16 '19 at 12:04graphicxpackage and place the$N_2(h)$in a\scalebox- see https://tex.stackexchange.com/a/31417/172926 – pip Feb 16 '19 at 12:44\text{\normalsize{Error }}, to shove it left a bit. Or a suitable\hspaceif 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 '19 at 13:18