# [OS X TeX] Working right with subequations

Christian Burk maillists at gmx.de
Tue Jan 2 13:30:54 EST 2007

Hallo,

I would like to use the subequations feature of amsmath.

I have an equation environment with \label{eq:1} and this equation is
numbered with 0.1.
Afterwards I have the subequations environment consisting of two
equations with \label{eq:1A} and \label{eq:1B}, but these two
equations are numbered 0.2a and 0.2b.

How could I achieve that the equations with the label 1A and 1B get
the number 0.1a and 0.1b?

Here is a picture of te status quo..
http://img211.imageshack.us/img211/7109/bild1rh9.png

and here my example...

------------
\documentclass[a4paper,12pt,chapterprefix,abstracton]{scrreprt}
\usepackage{amsmath}

\begin{document}

$$\label{eq:1} \underline{M} \ \underline{\ddot{u}} + \underline{C} \ \underline{\dot {u}} + \underline{S} \ \underline{u} = \underline{f}$$

\begin{subequations}
\begin{align}
u &= \left(\begin{array}{c}u_1 \\ \vdots \\ u_k \\ \vdots \\ u_N
\end{array}\right) \label{eq:1A} \\
u &= \left(\begin{array}{c}u_2 \\ \vdots \\ u_k \\ \vdots \\ u_N
\end{array}\right) \label{eq:1B}
\end{align}
\end{subequations}

\end{document}

------------

Christian