Using brackets for math

Question

The question is very simple:

Is there another type of bracket that can grow as the equation increases in size?

I wish it could look like this:

But unfortunately I only got this:

\documentclass{article}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}

\begin{document}
\begin{equation}
\int\int_D[\int_0^{16-x^2-y^2}(8+x+y)\,dz]\,dA
\end{equation}

\end{document}

https://tex.stackexchange.com/questions/38868/big-parenthesis-in-an-equation — Torbjørn T., Jun 27 '17 at 16:19
@samcarter the ghost of egreg will haunt you if you use \bigg rather than \biggl...\biggr — David Carlisle, Jun 27 '17 at 16:31
@DavidCarlisle Oh no! I'm only about 6.5 hours away from him, with his motorcycle he could be here by witching hour! — samcarter_is_at_topanswers.xyz, Jun 27 '17 at 16:37

sk8forether · Accepted Answer · 2017-06-27T17:26:05.550

5

I prefer this method using \left[ and \right] which resizes for you:

\documentclass{article}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}

\begin{document}
\begin{equation}
\int\int_D\left[\int_0^{16-x^2-y^2}(8+x+y)\,dz\right]\,dA
\end{equation}

\end{document}

Which looks like this:

Or, taking Mico's good suggestion, you can write:

\documentclass{article}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}

\begin{document}
\begin{equation}
\iint_D\left[\int_0^{16-x^2-y^2}(8+x+y)\,dz\right]\,dA
\end{equation}

\end{document}

edited Jun 27 '17 at 17:26

answered Jun 27 '17 at 16:24

sk8forether

342

1

Which you can also see in some cases have a tendency to get overly large – daleif Jun 27 '17 at 16:25
@daleif Actually, the size matches the OP's desired picture quite well... And, I prefer the size myself. – sk8forether Jun 27 '17 at 16:28
2

For display math, Knuth strongly recommends (in the TeXbook) writing \int\!\!\!\int (three negative thinspaces). Since the amsmath package is loaded, one could also write \iint. – Mico Jun 27 '17 at 16:43
1

@Mico Thanks, I often forget I can do that. Added it to my answer. – sk8forether Jun 27 '17 at 17:26

score 2 · Answer 2 · answered Jun 27 '17 at 16:42

2

Some suggestions:

Use \biggl[ and \biggr], not \left[ and \right], to size the square brackets.
Use \iint instead of \int\int for the pair of "outer" integral symbols.
"Snug up" the integrand to the inner integral symbol by issuing the directive \mkern-6mu or, equivalently, the directive \!\! (two negative thinspaces). You may even try \mkern-9mu for a "really snug" look.

\documentclass{article}
\usepackage{amsmath} % for "\iint" macro
\begin{document}
\begin{equation}
\iint_D\biggl[\int_0^{16-x^2-y^2}\mkern-6mu(8+x+y)\,dz\biggr]dA
\end{equation}
\end{document}

answered Jun 27 '17 at 16:42

Mico

506,678

would you mind to explain why you'd rather use \biggl[ than \left[? I really appreciate the adaptability of the left kind of brackets. Is this not a notorious advantage? – loved.by.Jesus Mar 19 '22 at 21:58
@loved.by.Jesus - A hallmark of superior typography is visual balance. For the equation at hand, using \left and \right to auto-size the square brackets ends up producing brackets are needlessly big -- too big, in fact, thereby distracting from the material they enclose. At other times, \left and \right can produce delimiters that are not large enough. For a longer discussion see, e.g., this answer to the query Is it ever bad to use \left and \right? [Shameless self-citation alert!] – Mico Mar 19 '22 at 23:58

Using brackets for math

2 Answers2