# [Tex/LaTex] How to place and number 3 short equations in one line

equationshorizontal alignment

I have 3 short equations which consume much vertical space, if each one is typeset in a separate line.

• How can I typeset them in one line in a "mathematically correct" way?
I do not necessarily need separate labels for each one of them: one label (and equation number would be enough)

\documentclass[11pt, a4paper]{scrbook}

\usepackage[ngerman]{babel}
\usepackage{array, amsmath}

\begin{document}

\begin{eqnarray}
x_{1} &= & \frac{A-A_{0}}{\frac{1}{2}\cdot \left( A_{\mathrm{A}} - A_{\mathrm{a}} \right)}
\label{exv:eqn:UmrechnungEingangsgroesse1} \\
x_{2} &= & \frac{B-B_{0}}{\frac{1}{2}\cdot \left( B_{\mathrm{A}} - B_{\mathrm{a}} \right)}
\label{exv:eqn:UmrechnungEingangsgroesse2} \\
x_{3} &= &  \frac{C-C_{0}}{\frac{1}{2}\cdot \left( C_{\mathrm{A}} - C_{\mathrm{a}} \right)}
\label{exv:eqn:UmrechnungEingangsgroesse3}
\end{eqnarray}
\end{document}


First of all, Avoid eqnarray.

You can use a normal equation environment and separate the equations with a \qquad.

\documentclass[11pt, a4paper]{scrbook}

\usepackage[ngerman]{babel}
\usepackage{amsmath}

\begin{document}

$$x_{1} = \frac{A-A_{0}}{\frac{1}{2}\cdot \left( A_{\mathrm{A}} - A_{\mathrm{a}} \right)} \qquad x_{2} = \frac{B-B_{0}}{\frac{1}{2}\cdot \left( B_{\mathrm{A}} - B_{\mathrm{a}} \right)} \qquad x_{3} = \frac{C-C_{0}}{\frac{1}{2}\cdot \left( C_{\mathrm{A}} - C_{\mathrm{a}} \right)} \label{exv:eqn:UmrechnungEingangsgroesse3}$$
\end{document}


(In my original answer I used an align environment, but this isn't really "correct", as that is meant for aligning equations over more than one line. As this only has one line, it is more appropriate to use an equation environment, as commented by Andrew Stacey.)