From my code below, how do I:
increase the spacing between the rows (as the denominator of the top fraction is too close to the numerator of the bottom fraction).
reduce the spacing between the '+' signs
Here is my code:
\documentclass{article}
\usepackage{amsmath}
\usepackage{arydshln}
\begin{document}
\begin{equation}
\dfrac{d\mathbf{P}_{T}}{dt} = {\begin{pmatrix}
\dfrac{dx}{dt} \\ \dfrac{dy}{dt} \\ \dfrac{dz}{dt}
\end{pmatrix}} ={\begin{pmatrix}
\dfrac{dx}{d\theta_{1}} \dfrac{d\theta_{1}}{dt} & + & \dfrac{dx}{dr_{2}} \dfrac{dr_{2}}{dt} & + & \dfrac{dx}{dr_{3}} \dfrac{dr_{3}}{dt}\\ \dfrac{dy}{d\theta_{1}} \dfrac{d\theta_{1}}{dt} & + & \dfrac{dy}{dr_{2}} \dfrac{dr_{2}}{dt} & + & \dfrac{dy}{dr_{3}} \dfrac{dr_{3}}{dt} \\ 0 && 0 && 0
\end{pmatrix}}
\end{equation}
\end{document}
\begin{pmatrix}
and\end{pmatrix}
. – egreg Oct 7 '15 at 20:46