7

By default the style is

\renewcommand{\theequation}{\thechapter.\arabic{equation}}

for example

            x+y =4         (2.1)

How to put \dots in front equation numbering such as

            x+y =4      ...(2.1)

while in the text reference remain (2.1).

and how to make it for the array by using \begin{eqnarray} \end{eqnarray}

      x = y+ 4         
         -Z+ E         
        + 4gh     ...(2.1)
1
  • Welcome to TeX-SX! Have a look at our starter page for a quick intro if you wish to familiarize yourself with our format. Commented Jul 25, 2013 at 6:26

2 Answers 2

9

The »mathtools« package provides the macros \newtagform and \usetagform which allow to do this quite comfortable.

\documentclass[11pt]{article}
\usepackage[T1]{fontenc}

\usepackage{mathtools}  % loads »amsmath«
\newtagform{dots}{\ldots(}{)}

\begin{document}
  \begin{equation}
    (a+b)^2 = a^2+2ab+b^2 \label{eqn:binomi-one}
  \end{equation}
  \begin{equation}
    (a-b)^2 = a^2-2ab+b^2 \label{eqn:binomi-two}
  \end{equation}
  \begin{equation}
    \usetagform{dots}
    (a+b)(a-b) = a^2-b^2 \label{eqn:binomi-three}
  \end{equation}
%
  The Binomi equations~\eqref{eqn:binomi-one},~\eqref{eqn:binomi-two} and~\eqref{eqn:binomi-three}.
\end{document}

Works of course also with the numbering scheme for equations in report and book.


enter image description here

3
  • How about the \begin{eqnarray} \usetagform{dots} \end{eqnarray} , I try to use it but cant get it
    – YIT HOE NG
    Commented Jul 25, 2013 at 9:08
  • @YIT HOE NG You shouldn't use eqnarray in your documents. You should use the environments provided by amsmath instead. Commented Jul 25, 2013 at 12:17
  • @YITHOENG: Avoid eqnarray! I'm not aware of a solution that works inside the environments of »amsmath«. Commented Jul 25, 2013 at 15:49
5

You can update the \maketag@@@ macro of amsmath to insert the \dots. Here's a convenience macro that you can add to your document preamble:

\makeatletter
\newcommand{\adddotsbeforeeqnnum}{\def\maketag@@@##1{\hbox{\m@th\normalfont\dots##1}}}
\makeatother

It acts as a switch to enable "dotted equation numbering".

enter image description here

\documentclass{article}
\usepackage{amsmath}% http://ctan.org/pkg/amsmath
\renewcommand{\theequation}{2.\arabic{equation}}% Just for this example
\makeatletter
\newcommand{\adddotsbeforeeqnnum}{\def\maketag@@@##1{\hbox{\m@th\normalfont\dots##1}}}
\makeatother
\begin{document}
\begin{equation}
  f(x) = ax^2 + bx + c \label{eqn:one}
\end{equation}
\begin{equation}
  f(x) = ax^2 + bx + c \tag{xyz}\label{eqn:two}
\end{equation}
\begin{equation}
  \adddotsbeforeeqnnum
  f(x) = ax^2 + bx + c \label{eqn:three}
\end{equation}
See~\eqref{eqn:one},~\eqref{eqn:two} and~\eqref{eqn:three}.
\end{document}
1
  • How about using the \begin{eqnarray} A= \left[\colvec{ A_{11}&A_{12}&\cdots &A_{1n}\A_{21}&A_{22}&\cdots &A_{2n}\\vdots & \vdots &\ddots &\vdots \A_{n1}&A_{n2}&\cdots &A_{nn}\}\right], \label{Equat2.4} \end{eqnarray}
    – YIT HOE NG
    Commented Jul 25, 2013 at 8:59

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