# Tufte LaTeX not recognizing subequations and \usepackage[table]{xcolor}

I have a LaTeX document that I want to put in tufte format. However, when I compile it is not reconizing the \begin{subequations} (I used \usepackage and not accepting the \usepackage[table]{xcolor} that I used so my matrices have columns painted gray. Does anyone knows why this is happening?

A minimal working example where I show the packages I used and the type of things I want to do:

\documentclass{tufte-book}

\usepackage{lipsum}
\usepackage{booktabs}
\usepackage{graphicx}
\setkeys{Gin}{width=\linewidth,totalheight=\textheight,keepaspectratio}
\graphicspath{{graphics/}}
\usepackage{fancyvrb}
\fvset{fontsize=\normalsize}
\usepackage{xspace}
\usepackage{units}

%Packages I included
\usepackage{transparent}
\usepackage[table]{xcolor}
\usepackage{listings}
\usepackage{amsthm}
\usepackage{bbm}

\begin{document}

\begin{align*}
\begin{array}{cc}
\cellcolor{gray!25} 2 & \cellcolor{gray!25} 3 \\
1 & 4
\end{array}
\right)}_{A}
\left(
\begin{array}{c}
\cellcolor{gray!25} v_{1}  \\
\cellcolor{gray!25} v_{2}
\end{array}
\end{align*}

$A^{-1}$ is a matrix such that:
\begin{subequations}
\begin{align}
A \cdot A^{-1}&=A^{-1} \cdot A=I\,, \\
\left(A^{-1} \right) ^{-1}&=A\,, \\
\left( A^{t} \right) ^{-1}&=\left( A^{-1} \right)^{t}\,, \\
\left( A \cdot B \right)^{-1}&=B^{-1} \cdot A^{-1}\,.
\end{align}
\end{subequations}
\end{document}


Some of the errors:

! LaTeX Error: Option clash for package xcolor.
! LaTeX Error: Environment subequations undefined.


I use TexMaker and TeX Live 2012 (Mac OS 10.7.5) Thank you!

• Also it is not recognizing \begin{align}! ! LaTeX Error: Environment align undefined. – Elisa Jun 13 '13 at 21:04
• Welcome to TeX.SX! You can have a look on our starter guide to familiarize yourself further with our format. Please add a minimal working example (MWE) that illustrates your problem. It will be much easier for us to reproduce your situation and find out what the issue is when we see compilable code, starting with \documentclass{...} and ending with \end{document}. – Henri Menke Jun 13 '13 at 21:08
• the subequations environment is defined in amsmath, not in any of the other packages you have listed here. are these all the packages you are using, and what is your document class. the align environment is also defined in amsmath. (welcome to tex.sx.) – barbara beeton Jun 13 '13 at 21:17

Let's handle each error one at a time:

! LaTeX Error: Option clash for package xcolor.


This error occurs because the tufte-book document class is loading the xcolor package but isn't providing the table option. To get around this issue, add this line before the \documentclass line:

\PassOptionsToPackage{table}{xcolor}% must be *before* \documentclass
\documentclass{tufte-book}


Now:

! LaTeX Error: Environment subequations undefined.


This error is because the amsmath package hasn't been loaded. Add \usepackage{amsmath} and this error should go away.