# How to format a matrix system of equations in LATEX

By adding \vphantom{\dpartial{u}{p}} to elements of vector:

\documentclass{article}

\usepackage{amsmath}
\newcommand{\dpartial}[2]{\frac{\partial #1}{\partial #2}}
\usepackage{etoolbox}
\AtBeginEnvironment{bmatrix}{\everymath{\displaystyle}} % \displaystyle systems of equations

\begin{document}
$$\begin{bmatrix} m\dpartial{u}{T} & m\dpartial{u}{p} \\ -m\left(T\dpartial{R}{T} + R\right) & V - mT\dpartial{R}{p} \end{bmatrix} % \begin{bmatrix} \dot{T}\vphantom{\dpartial{u}{p}} \\ \dot{p}\vphantom{\dpartial{u}{p}} \end{bmatrix} = % \begin{bmatrix} \dot{Q} - p\dot{V} + \dot{m}(h-u) - m\dpartial{u}{\phi}\dot{\phi} \\ \dot{m}RT + mT\dpartial{R}{\phi}\dot{\phi} - p\dot{V} \end{bmatrix}$$
\end{document}


Addendum: Considering to @Mico comment, you will get better looking matrices and vector by inserting some vertical space between their rows. This you can achieve on many ways, for example:

• by terminate rows with \\[2ex]
• by inserting \addlinespace determined in the booktabs package:
\documentclass{article}
\usepackage{booktabs}

\usepackage{amsmath}
\newcommand{\dpartial}[2]{\frac{\partial #1}{\partial #2}}
\usepackage{etoolbox}
\AtBeginEnvironment{bmatrix}{\everymath{\displaystyle}} % \displaystyle systems of equations

\begin{document}
$$\begin{bmatrix} m\dpartial{u}{T} & m\dpartial{u}{p} \\ \addlinespace -m\biggl(T\dpartial{R}{T} + R\biggr) & V - mT\dpartial{R}{p} \end{bmatrix} % \begin{bmatrix} \dot{T}\vphantom{\dpartial{u}{p}} \\ \addlinespace \dot{p}\vphantom{\dpartial{u}{p}} \end{bmatrix} = % \begin{bmatrix} \dot{Q} - p\dot{V} + \dot{m}(h-u) - m\dpartial{u}{\phi}\dot{\phi} \\ \addlinespace \dot{m}RT + mT\dpartial{R}{\phi}\dot{\phi} - p\dot{V} \end{bmatrix}$$
\end{document}


• by use of \makegapedcells defined in the makecell package:
\documentclass{article}
\usepackage{makecell}

\usepackage{amsmath}
\newcommand{\dpartial}[2]{\frac{\partial #1}{\partial #2}}
\usepackage{etoolbox}
\AtBeginEnvironment{bmatrix}{\everymath{\displaystyle}} % \displaystyle systems of equations

\begin{document}
$$\setcellgapes{5pt} \makegapedcells \begin{bmatrix} m\dpartial{u}{T} & m\dpartial{u}{p} \\ -m\biggl(T\dpartial{R}{T} + R\biggr) & V - mT\dpartial{R}{p} \end{bmatrix} % \begin{bmatrix} \dot{T}\vphantom{\dpartial{u}{p}} \\ \dot{p}\vphantom{\dpartial{u}{p}} \end{bmatrix} = % \begin{bmatrix} \dot{Q} - p\dot{V} + \dot{m}(h-u) - m\dpartial{u}{\phi}\dot{\phi} \\ \dot{m}RT + mT\dpartial{R}{\phi}\dot{\phi} - p\dot{V} \end{bmatrix}$$
\end{document}