# Using brackets for math [duplicate]

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

\end{document}


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

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

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

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

\end{document}


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

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}
$$\iint_D\biggl[\int_0^{16-x^2-y^2}\mkern-6mu(8+x+y)\,dz\biggr]dA$$
\end{document}