Btukfyl

We can write Row names (R1, R2, R3) in each row

How to write Column names (C1, C2, C3) below each column?

documentclass[10pt,dvipsnames,svgnames]{beamer}

setbeamertemplate{navigation symbols}{}

usepackage{amsmath}



usefonttheme[onlymath]{serif}

usefonttheme{professionalfonts}



usepackage{colortbl}



begin{document}

begin{frame}

begin{align*}

A &=

left|begin{array}{ccc}

rowcolor{orange!15}

y+k & y & y \

y & y+k & y \

y & y & y+k \

end{array}

right|

begin{array}{l}

R_1\

R_2\

R_3

end{array}\ \

%

&=

left|begin{array}{c>{columncolor{red!25}}cc}

y+k & y & y \

y & y+k & y \

y & y & y+k \

end{array}

right|

begin{array}{l}

%rowcolor{yellow!15}

C_1\

C_2\

C_3

end{array}

end{align*}



end{frame}

end{document}

In your setup of a stacked equation containing matrices, you can use the following:

documentclass{beamer}



usepackage{amsmath,eqparbox}

usepackage{colortbl}



begin{document}



begin{frame}

  begin{align*}

    A &= left| begin{array}{ c c c }

      rowcolor{orange!15}

      y + k &   y   &   y   \

        y   & y + k &   y   \

        y   &   y   & y + k

    end{array}right|

    begin{array}{ l }

      R_1 \

      R_2 \

      R_3

    end{array} \[-normalbaselineskip]

    &= begin{array}{@{} c @{}}

      \

      left|begin{array}{ c >{columncolor{red!25}}c c }

        eqmakebox[L]{$y + k$} &   y   &   y   \

          y   & eqmakebox[C]{$y + k$} &   y   \

          y   &   y   & eqmakebox[R]{$y + k$}

      end{array}right| \

      eqmakebox[L]{$C_1$}hspace{2arraycolsep}eqmakebox[C]{$C_2$}hspace{2arraycolsep}eqmakebox[R]{$C_3$}

    end{array}

  end{align*}

end{frame}



end{document}