How to put a big bracket under different parts of a equation so that I could write e.g. a text specific to that part in the equation?

How to put a big bracket under different parts of a equation so that I could write e.g. a text specific to that part in the equation?

For example :

f =  x^3 +  2
|___|  |__|
|     |
text 1  text 2

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Welcome to TeX.sx! Your question was migrated here from Stack Overflow. Please register on this site, too, and make sure that both accounts are associated with each other, otherwise you won't be able to comment on or accept answers or edit your question. –  Werner Feb 17 '12 at 4:47

migrated from stackoverflow.comFeb 17 '12 at 4:20

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What you want is

f = \underbrace{x^3}_\textrm{text 1} + \underbrace{2}_\textrm{text 2}

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Since the text used in \underbrace (or \overbrace) is typically set in a different font size to not distract further from the equation, it is preferable to use amsmath's \text macro.

\documentclass{article}
\usepackage{amsmath}% http://ctan.org/pkg/amsmath
\begin{document}
$f(x) = \underbrace{(x+2)^3}_\text{text 1} + \overbrace{(x-3)}^\text{text 2}$
\end{document}

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Would you still use \text if you wanted to include math? e.g., instead of "text 1" I want to have something like $g(x)$. (Also, congrats on your 1000th answer. Awesome work!) –  Mike Wierzbicki Feb 17 '12 at 6:12
@MikeWierzbicki: Thanks - 1000! No, if you use math, then you would not use \text, since math will automatically size to the appropriate font size. The switching of mode (from math to text) causes default settings to be invoked, setting text in \normalsize rather than \scriptsize. amsmath's \text chooses the appropriate text font size via \mathchoice. –  Werner Feb 17 '12 at 6:28