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

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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
The question mentions "brackets", while the answers below provide "braces". For a bracket approach, there is this question: tex.stackexchange.com/questions/161459/… – Steven B. Segletes Jan 22 '15 at 0:06

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}
\begin{document}
$f(x) = \underbrace{(x + 2)^3}_\text{text 1} + \bigl( \mathrlap{\overbrace{\phantom{(c - 2d)}}^{\text{text 2}}} (c - \mathrlap{\underbrace{\phantom{2d) + (3e}}_{\text{text 3}}} 2d) + \overbrace{(3e - 4f)}^{\text{text 4}} \bigr) + \overbrace{(x - 3)}^\text{text 5}$
\end{document}


The difficult overlapping braces uses math overlaps from mathtools. It follows a process of setting the \over-/\underbrace text first with a \phantom base, after which the base (or part thereof) is re-set. However, if those aren't needed, using amsmath only would suffice for usage of \text.

There are a number of ways of achieving the overlapping output. Another method of overlapping braces is discussed in section 63.2 Overlapping braces of the mathmode 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
Perhaps the single most useful answer on this entire forum – Beached Whale Jul 20 at 1:24

What you want is

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

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You would find it out in the mathmode manual or symbols manual.

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Please provide hyperlinks for the manuals. Not everybody may know where to find them. (I've added them for you.) Also you should consider providing more information. The poster may not know what to look for. – Marc van Dongen Feb 17 '12 at 7:53
The link to mathmode manual gives me a 404. – Reb.Cabin Mar 21 at 19:56