5

I have this code:

\documentclass[a4paper,11pt]{article}

\usepackage{amsmath}

\begin{document}

$
A = \begin{bmatrix}
a & b & c & d \\
a & b & c & d \\
a & b & c & d \\
a & b & c & d \\
\end{bmatrix}
$

\end{document}

What I want to do is change the color of the first and third column to red.

enter image description here

5

If you want to automate this process for an entire column, then you need to have access to the column specification. This is not possible via amsmath's *matrix environments. Instead, use array and insert \color{red} in front of every entry using the >{<prefix>} specification:

enter image description here

\documentclass{article}

\usepackage{amsmath,array,xcolor}

\begin{document}

$
  A = \begin{bmatrix}
    a & b & c & d \\
    a & b & c & d \\
    a & b & c & d \\
    a & b & c & d
  \end{bmatrix} \qquad
  \left[\begin{array}{@{} >{\color{red}}c c >{\color{red}}c c @{}}
    a & b & c & d \\
    a & b & c & d \\
    a & b & c & d \\
    a & b & c & d
  \end{array}\right] = A
$

\end{document}
3

A Little bit easier!

\documentclass[a4paper,11pt]{article}

\usepackage{amsmath}
\usepackage{color}

\begin{document}

\[
A =
\def\b{b}
\def\d{d}
\def\a{\color{red}a}
\def\c{\color{red}c}
\begin{bmatrix}
\a & \b & \c & \d \\
\a & \b & \c & \d \\
\a & \b & \c & \d \\
\a & \b & \c & \d \\
\end{bmatrix}
\]

\end{document}

enter image description here

  • 1
    I'm sure the OP made the matrix A have similar rows out of ease for a minimal example. In general, how would your suggestion be "easier" if the columns had arbitrary content in them? – Werner Jan 26 '17 at 20:06
  • @Werner: I don't claim to offer something generic. My assumption was this is what the OP needs, inherently. Actually, I was not as sure as you are! :D – Roboticist Jan 26 '17 at 20:10
  • Werner is right. However, thank you for your answer @Roboticist. It can be useful for another purpose ! – Thanasis1101 Jan 26 '17 at 20:18
1

Based on How to color math symbols? or Simpler way to add color to equations in math mode? (I googled "math color latex").

\documentclass[a4paper,11pt]{article}

\usepackage{amsmath}

\usepackage{xcolor}

\begin{document}

\begin{equation}
A = \begin{bmatrix}
\textcolor{red}{a} & b & \textcolor{red}{c} & d \\
\textcolor{red}{a} & b & \textcolor{red}{c} & d \\
\textcolor{red}{a} & b & \textcolor{red}{c} & d \\
\textcolor{red}{a} & b & \textcolor{red}{c} & d \\
\end{bmatrix}
\end{equation}

\end{document}

enter image description here

  • I wanted an automatic way to change the color of the columns (like the accepted answer), but thank you for your answer ! – Thanasis1101 Jan 26 '17 at 20:15

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.