Math & Science ⇒ Brace over a System of two numbered Equations

[ppcombes]

Hi,

I would like to add a single left brace over the two lines of the following system, while keeping the separate numbering of each line but I have not managed yet.

Code: Select all

\begin{eqnarray}
&&\log w_{i} =
 C_{i}\, a_{1}+ F_{j(i)}\, a_{2}+L_{c(i)s(j(i))}\, a_{3}+\delta_{c(i)}+\varepsilon_{i}\label{eq:step1}\\[1ex]
&&\delta_{c} = U_{c}\, \alpha +\nu_{c}\label{eq:step2}
\end{eqnarray}

Thanks for your help.

[localghost]

Avoid eqnarray! The amsmath package (perhaps enhanced by mathtools) provides much better math environments. In this case you could use empheq (see below code).

Code: Select all

\documentclass[11pt]{article}
\usepackage[T1]{fontenc}
\usepackage{empheq}  % loads »mathtools«, which in turn loads »amsmath«

\begin{document}
  \begin{empheq}[left=\empheqlbrace]{align}
    \log w_i &= C_i\, a_1+F_{j(i)}\, a_2+L_{c(i)s(j(i))}\, a_3+\delta_{c(i)}+\varepsilon_i \label{eq:step1} \\
    \delta_c &= U_c\, \alpha+\nu_c\label{eq:step2}
  \end{empheq}
\end{document}

As an alternative there is the numcases environment from the cases package. A look at the corresponding manuals is recommended to understand what they do.


Best regards and welcome to the board
Thorsten