4

please help me to create this in LaTeX:

enter image description here

5 Answers 5

1

I did not solve exactly your problem but a similar one from which you could extract useful information.

I needed to solve a determinant far more general. I used plain TikZ and the matrix function inside TiKZ. Here is the code.

\documentclass[12pt]{article}
\usepackage[pdftex]{graphicx}
\usepackage{pgfplots,tikz}
\usetikzlibrary{matrix}
\begin{document}
\begin{tikzpicture}
  \matrix[
  , matrix of math nodes
  , left delimiter = {(}
  , right delimiter = {)}
  ] (m)
  {
      1 & \rho_1 & 0 & 0 & \cdots & 0 & 0 & \rho_{1}  \\
      \rho_1 & 1 & \rho_1 & 0 & \cdots & 0 & 0 & 0  \\
      0  & \rho_1 & 1 &  \rho_1 & \cdots & 0 & 0 & 0  \\
      \vdots &  & \ddots & \ddots & \ddots & & \vdots & \vdots  \\
       \vdots &  &  & \ddots & \ddots & \ddots & \vdots & \vdots \\
      \vdots &  &  &  & \rho_1 & 1 & \rho_1 & 0  \\
      \vdots & & & & & \rho_1 & 1 & 0  \\
      0 & \cdots & \cdots & \cdots & \cdots & 0  &  \rho_1  & 0 \\
  };
  \coordinate (A) at (2.5,2.6);
  \coordinate (B) at (-3.0,2.65);
  \coordinate (C) at (2.55,-2.7);
  \draw[red, dotted, line width=2]  (A) circle(9pt);
  \draw[red,  line width=2]  (B)--++(5.2,0);
  \draw[red,  line width=2]  (C)--++(0,4.9);

\end{tikzpicture}

\end{document}

To be honest, I computed the length and positions for the segments and circles by trial and error. Sure, there should be a way to get these locations from the matrix environment in an elegant way. I do not know how to do this.

Here is the figure.

enter image description here

8
\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{fit}

\newcommand{\tikzmark}[2]{\tikz[overlay,remember picture,baseline=(#1.base)] \node (#1) {#2};}

\begin{document}
\[
 \left[\begin{array}{*3{c}}
    \tikzmark{left_end}{0} & 2 & \tikzmark{right_end}{1}\\
    3 & -1 & 2 \\
    \tikzmark{down_left}{4} & 0 & \tikzmark{down}{1}
  \end{array}\right]
\]
\tikz[overlay,remember picture] {
\draw[red,thick,dashed] (left_end) circle (0.2cm);
    \draw[-,red,thick] (left_end) -- ++ (1.7,0) (right_end);
    \draw[-,red,thick] (left_end) -- ++ (0,-1.) (down_left);
}
\end{document}

enter image description here

4
  • @Said Please mark it as an answer to close your question. Feb 22, 2019 at 14:34
  • I posted some extended comments below. If you address them in your answer, I will be happy to remove them.
    – user121799
    Feb 22, 2019 at 16:00
  • Thanks @marmot. Interesting comments and smoother solution. Feb 22, 2019 at 16:05
  • You can really take them over, I do not want to post an answer here. I just want to avoid that \tikzmark gets redefined.
    – user121799
    Feb 22, 2019 at 16:07
7

This is more an extended comment on the answer by Sina Ahmadi. I will be happy to remove this if in that answer a few things get changed.

  1. \tikzmark is a phantastic command that is part of the tikzmark library. I would like to argue that creating a new command with this name is not a good practice.
  2. The nodes right_end and down_left are not used. The lines are drawn as determined by the two hard-coded distances - ++ (1.7,0) and - ++ (0,-1.).

\documentclass{article}
\usepackage{amsmath}
\usepackage{tikz}
\usetikzlibrary{tikzmark}

\begin{document}
\[\begin{bmatrix}
    \tikzmarknode[circle,draw=red,inner sep=0.5pt,densely dashed]{A11}{0} & 2 & \tikzmarknode{A13}{1}\\
    3 & -1 & 2 \\
    \tikzmarknode{A31}{4} & 0 & 1
 \end{bmatrix} 
\]
\begin{tikzpicture}[overlay,remember picture] 
\draw[red] (A11.east) -- (A11.east-|A13.east)
(A11.south) -- (A11.south|-A31.south);
\end{tikzpicture}
\end{document}

enter image description here

1
  • @Said You're welcome! (BTW, you can only accept one answer. Given that you accepted Sina's answer first, you might want to place the tick there.)
    – user121799
    Feb 22, 2019 at 22:04
4

A simple code with pstricks and mathtools:

\documentclass[svgnames]{article}
\usepackage{mathtools} 
\usepackage{pst-node, auto-pst-pdf}

\begin{document}

\begin{postscript}
\psset{{linecolor=DeepPink}, framesep=2pt, nodesepB=-8pt}
\[ \begin{bmatrix}
\mathclap{\circlenode[linestyle=dashed, dash=3.5pt 2.5pt]{A}{0}} & 2 & \rnode{C}{1} \\
3 & -1 & 2 \\
\rnode{B}{4} & 0 & 1 
\end{bmatrix} \]
\ncline{A}{B}
\ncline{A}{C}
\end{postscript}

\end{document} 

enter image description here

Ensure you have --enable-write18 in your LaTeX command/engine so that auto-pst-pdf works.

0
1

It's possible to do that with nicematrix. This package creates a PGF/Tikz node under each cell of the array. Then, it's possible to use tikz to draw what we want.

\documentclass[svgnames]{article}

\usepackage{nicematrix}
\usepackage{tikz}

\begin{document}

$\begin{bNiceMatrix}[margin]
0 & 2  & 1 \\
3 & -1 & 2 \\
4 & 0  & 1
\CodeAfter
\begin{tikzpicture} [color = DeepPink]
\draw [dashed] (1-1) circle (2mm) ;
\draw ([xshift=2mm]1-1.east) -- ([xshift=2mm]1-3.east) ;
\draw ([yshift=-1mm]1-1.south) -- ([yshift=-1mm]3-1.south) ;
\end{tikzpicture}
\end{bNiceMatrix}$

\end{document}

Result of the above code

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