Underbracing matrix

Question

How to make that look OK? Please help!

Welcome to TeX.SE! Please provide your code as text to make it easier to look for solutions. Also: please specify what 'looks OK' is in this case. — Marijn, Feb 03 '16 at 12:34
include the \left(...\right) inside the \underbraceand remove $ $ after \det — percusse, Feb 03 '16 at 12:41
Screen shots can be hard to read so it is much better to cut and paste your code into the gui (and highlight it using the {} button). This way people can read it more easily and they can copy and use it when they try to solve your problem. — , Feb 03 '16 at 12:58

score 2 · Accepted Answer · edited Apr 13 '17 at 12:34

2

You can adapt my answer https://tex.stackexchange.com/a/145718/4427

\documentclass{article}
\usepackage{amsmath}

\newcommand{\underbracedmatrix}[2]{%
  \left(\;
  \smash[b]{\underbrace{
    \begin{matrix}#1\end{matrix}
  }_{#2}}
  \;\right)
  \vphantom{\underbrace{\begin{matrix}#1\end{matrix}}_{#2}}
}

\begin{document}
\[
\Delta_n=\det
  \underbracedmatrix{
    A & B \\
    B & A & B \\
      & B & \ddots & \ddots \\
      &   & \ddots & \ddots & B \\
      &   &        & B      & A
  }{n\times n}
\]
\end{document}

edited Apr 13 '17 at 12:34

Community

1

answered Feb 03 '16 at 12:42

egreg

1,121,712

Thank you! Now I will try to understand that :) My first time using TeX. – Andrii V. Feb 03 '16 at 12:46

Underbracing matrix

1 Answers1