Overful hbox when using \colorbox in math mode

Question

I got pretty long math formulas in my LaTeX document. Now I want to color the background of those formulas. However, if I use \colorbox{}{} the linebreak doesn't work anymore.

Note: the gray bar at the right side of the images marks the end of the page and the "Das" you can see at the bottom of the images marks the end of the line. The downarrow marks the middle of the line.

1. This is centered and the linebreak works:

\begin{center}
    \(32x^{15}+91x^{14}+11x^{13}+120x^{12}+209x^{11}+114x^{10}+220x^{9}+77x^{8}+67x^{7}+64x^{6}+236x^{5}+17x^{4}+236x^{3}+17x^{2}+236x+17x\)
\end{center}

2. Here the linebreak doesn't work and the \hbox is overfull:

\[32x^{15}+91x^{14}+11x^{13}+120x^{12}+209x^{11}+114x^{10}+220x^{9}+77x^{8}+67x^{7}+64x^{6}+236x^{5}+17x^{4}+236x^{3}+17x^{2}+236x+17x\]

3. Here the background is colored, but the linebreak doesn't work anymore:

\begin{center}
    \colorbox{grn}{
        \(32x^{15}+91x^{14}+11x^{13}+120x^{12}+209x^{11}+114x^{10}+220x^{9}+77x^{8}+67x^{7}+64x^{6}+236x^{5}+17x^{4}+236x^{3}+17x^{2}+236x+17x\)
    }
\end{center}

I already tried multiple different things, but couldn't find a solution, that worked for me. So how can I have the math formulas centered and the background colored at the same time without having an overfull hbox?

Any help is appreciated.

https://tex.stackexchange.com/a/75133/134144 might be interesting. — leandriis, Dec 28 '20 at 10:22
please always give a complete small testfile not just fragments, it makes testing answers much easier — David Carlisle, Dec 28 '20 at 10:59

score 3 · Answer 1 · answered Dec 28 '20 at 10:41

I'd not rely on automatic line breaking in this case.

\documentclass{article}
\usepackage{amsmath,mathtools,xcolor}
\definecolor{grn}{RGB}{210,253,210}
\begin{document}
\begin{equation}
\begin{gathered}
32,91,11,120,209,114,220,77,67,64,236,17,236,17,236,17 \
\downarrow \
\colorbox{grn}{$\begin{multlined}
  32x^{15}+91x^{14}+11x^{13}+120x^{12}+209x^{11}+114x^{10}+220x^{9}+77x^{8} \
  +67x^{7}+64x^{6}+236x^{5}+17x^{4}+236x^{3}+17x^{2}+236x+17x
\end{multlined}$}
\end{gathered}
\end{equation}
\end{document}

score 3 · Accepted Answer · answered Dec 28 '20 at 10:55

The empheq package has tools for that:

\documentclass{article}
\usepackage{geometry} 
\usepackage{empheq}
\usepackage[svgnames]{xcolor}
\newcommand{\eqcolorbox}[1]{\colorbox{YellowGreen!25}{#1}}
\begin{document}
\begin{empheq}[box=\eqcolorbox]{gather*}
  32x^{15}+91x^{14}+11x^{13}+120x^{12}+209x^{11}+114x^{10}+220x^{9}+77x^{8}+67x^{7}+64x^{6}+ {}\
  236x^{5}+17x^{4}+236x^{3}+17x^{2}+236x+17x
\end{empheq}
\end{document}

score 2 · Answer 3 · answered Dec 28 '20 at 10:32

With tcolorbox and amsmath's gather:

\documentclass{article}
\usepackage[svgnames]{xcolor}
\usepackage[most]{tcolorbox}
\newtcolorbox{coloredequation}{ams gather*, 
                               colback=LightGreen, 
                               sharp corners,
                               boxrule=0pt,
                               frame hidden,}
\begin{document}
\begin{coloredequation}
  32x^{15}+91x^{14}+11x^{13}+120x^{12}+209x^{11}+114x^{10}+220x^{9}+77x^{8}\
  +67x^{7}+64x^{6}+236x^{5}+17x^{4}+236x^{3}+17x^{2}+236x+17x
\end{coloredequation}
\end{document}

Overful hbox when using \colorbox in math mode

3 Answers3