10

Good evening,

I'm trying to achieve following picture in latex, but i can't do it. Can someone help me? enter image description here

This is what I have so far:

\documentclass[a4paper,12pt]{scrartcl}

\usepackage{booktabs}
\usepackage[utf8] {inputenc}
\usepackage[ngerman]{babel}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{amsfonts}
\usepackage[T1]{fontenc}

\begin{document}

\begin{center}
      $\left(\begin{array}{rrrr}
             2&2&-1&3  \\
            \cmidrule{2-4}
             0&1&3&4  \\
             0&1&3&4  \\
             0&3&9&6  \\
             0&1&3&-2  
    \end{array}\right)$
\end{center}

\end{document}

2 Answers 2

14

You're missing the vertical line | in the column specification and a \multicolumn{1}{r} for the element in the top left corner:

enter image description here

\documentclass{article}

\begin{document}

\[
  \left(
    \begin{array}{ r | *{3}{r} }
      \multicolumn{1}{r}{2} & 2 & -1 &  3 \\
      \cline{2-4}
      0 & 1 &  3 &  4 \\
      0 & 1 &  3 &  4 \\
      0 & 3 &  9 &  6 \\
      0 & 1 &  3 & -2  
    \end{array}
  \right)
\]

\end{document}

For a more evenly distributed spacing around the last three columns, consider using \phantom{-}2 in the first row:

enter image description here

\documentclass{article}

\begin{document}

\[
  \left(
    \begin{array}{ r | *{3}{r} }
      \multicolumn{1}{r}{2} & \phantom{-}2 & -1 &  3 \\
      \cline{2-4}
      0 & 1 &  3 &  4 \\
      0 & 1 &  3 &  4 \\
      0 & 3 &  9 &  6 \\
      0 & 1 &  3 & -2  
    \end{array}
  \right)
\]

\end{document}
1
10

With nicematrix. The environments of nicematrix create PGF/Tikz nodes under the rows, columns and cells and the array and it's possible to use them to draw whatever you want with Tikz.

\documentclass{article}
\usepackage{nicematrix}
\usepackage{tikz}

\begin{document}

\[
\begin{pNiceMatrix}[r,right-margin,columns-width=auto]
  2 & 2 & -1 &  3 \\
  0 & 1 &  3 &  4 \\
  0 & 1 &  3 &  4 \\
  0 & 3 &  9 &  6 \\
  0 & 1 &  3 & -2  
\CodeAfter
\tikz \draw ([xshift=4pt]last-|2) |- (2-|last) ;
\end{pNiceMatrix}
\]

\end{document}

Output of the above code

5
  • Thank you very much! Dec 30, 2020 at 21:14
  • Is it also possible to draw dotted lines ? Dec 30, 2020 at 21:18
  • 1
    @Francesco: Yes. Put \draw [dotted] instead of \draw. Dec 30, 2020 at 21:29
  • To my eyes the horizontal line is a little too low.
    – graffe
    Dec 30, 2020 at 21:58
  • 1
    @Anush That's why this approach is more powerful. You only need e.g. \tikz \draw ([xshift=4pt]row-6-|col-2) |- ([yshift=2pt]row-2-|col-5) ;, or whatever yshift you like. And have access to many other things such as decorated lines.
    – user232027
    Jan 1, 2021 at 1:20

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.