increase the vertical space between rows of a matrix

Question

\documentclass{amsart}

\usepackage{amsmath}%
\usepackage{amsfonts}%
\usepackage{amssymb}%

\begin{document}

\begin{align*}
\tau_A
\begin{pmatrix} 
x \\ 
y 
\end{pmatrix}
=
\begin{pmatrix} 
\frac{4+5x+6y}{1+2x+3y} \\ 
\frac{7+8x+8y}{1+2x+3y} 
\end{pmatrix}
\end{align*}

\end{document}

This code has the following output:

Is there anyway to separate the elements in the right hand column vector in order to make the fractions clearer to distinguish?

Answer 1

You can increase specify extra an space to go between the rows after \\. You can also make the fractions bigger with \displaystyle if necessary.

\documentclass{amsart}

\usepackage{amsmath}%
\usepackage{amsfonts}%
\usepackage{amssymb}%

\begin{document}

\begin{align*}
\tau_A
\begin{pmatrix} 
x \\ 
y 
\end{pmatrix}
=
\begin{pmatrix} 
\displaystyle\frac{4+5x+6y}{1+2x+3y} \\[1cm]
\displaystyle\frac{7+8x+8y}{1+2x+3y} 
\end{pmatrix}
\end{align*}

\end{document}

Here I used 1cm to show the effect clearly; a space this big is probably excessive.

Answer 2

I have a solution with booktabs (so as to be sure one addsthe same vertical space throughout the document) or with cellspace:

\documentclass{amsart}

\usepackage{amsmath}%
\usepackage{amsfonts}%
\usepackage{amssymb}%
\usepackage{booktabs}
\setlength\defaultaddspace{0.5ex}
\usepackage[math]{cellspace}
\setlength\cellspacetoplimit{3pt}
\setlength\cellspacebottomlimit{3pt}

\begin{document}

\begin{align*}
  \texttt{With booktabs: }\qquad\tau_A
  \begin{pmatrix}
  x \\
  y
  \end{pmatrix}
  =
  \begin{pmatrix}
  \frac{4+5x+6y}{1+2x+3y} \\
  \addlinespace
  \frac{7+8x+8y}{1+2x+3y}
  \end{pmatrix}
\end{align*}

\begin{align*}
  \texttt{With cellspace: }\qquad\tau_A
  \begin{pmatrix}
  x \\
  y
  \end{pmatrix}
  =
  \begin{pmatrix}
  \frac{4+5x+6y}{1+2x+3y} \\
  \frac{7+8x+8y}{1+2x+3y}
  \end{pmatrix}
\end{align*}

\end{document}