Math & Science ⇒ Repeat Equation with original Number

[gliu]

In my research paper I have very early on inside the document the following.

Code: Select all

\begin{equation}
x^2 + y^2 = 1
\end{equation}

The auto numbering system numbered this equation as equation "2.1".

Now I want to have a way of displaying that equation once more, without having to type out the {equation} environment, because that would create a completely different number for the Equation which I don't want.

I want something like this.

Recall Equation 2.1:

[Display equation here with its number]

...

I'm using the report class, is it possible?

[svend_tveskaeg]

If the only problem is that the equation number becomes different, you can use the following:

Code: Select all

\documentclass{article}

\usepackage{amsmath}

\begin{document}
\[
x^2 + y^2 = 1 \tag{2.1}
\]
\end{document}

[alainremillard]

Just to complete Svend's answer, you could use label and reference to acheive this

Code: Select all

\documentclass{article}
    \usepackage{amsmath}
    \begin{document}
    \begin{equation}\label{myeqn}
        x^2 + y^2 = 1
    \end{equation}
    
    Recall equation~\eqref{myeqn}
    \begin{equation}
        x^2 + y^2 = 1 \tag{\ref{myeqn}}
    \end{equation}
\end{document}

Have a nice day
Alain Rémillard

[gliu]

Thank you for your help. I'm quite new to this language so the straight-up code helps a lot.

[gliu]

Just to complete Svend's answer, you could use label and reference to acheive this

Code: Select all

\documentclass{article}
    \usepackage{amsmath}
    \begin{document}
    \begin{equation}\label{myeqn}
        x^2 + y^2 = 1
    \end{equation}
    
    Recall equation~\eqref{myeqn}
    \begin{equation}
        x^2 + y^2 = 1 \tag{\ref{myeqn}}
    \end{equation}
\end{document}

Have a nice day
Alain Rémillard

But let's say I'm writing my document across different .tex files. Say I declare the equation x^2+y^2=1 in FileA.tex and then I want to ref. it in FileB.tex, how would I do this?

[cgnieder]

But let's say I'm writing my document across different .tex files. Say I declare the equation x^2+y^2=1 in FileA.tex and then I want to ref. it in FileB.tex, how would I do this?

This should also work when used across several included tex files. If it doesn't please provide a minimal working example so we can reproduce the issue.

Regards