Math & Science ⇒ Referring (and printing) back to a previous Equation

[jakethepeguk1]

Hello all,

I was hoping someone could help. I am using the \autoref{} function to refer back to previous equations, tables and figures with a lot of ease, however I've encountered a problem which may need a different solution.

In chapter 1 of a document i have printed an equation (using \begin{equation}... \end{equation}) and labelled it accordingly. The label is then 1.1.

I would then like to refer to the same equation in chapter 2. However instead of just referring back to it in the text, i would like to print it again (it is a tricky equation so i would like to have it on the page, rather than having to scroll back through lots of pages to get to it), keeping the same label, i.e. 1.1 rather than 2.1.

Is it possible to either print the equation in chapter two by using something like:

\input{eqn:chapter1:e1} - ( i know this wouldnt work, but something along these lines)

which prints exactly the same equation, with the same label (which would be ideal), or input the equation again using \begin{equation}..., but printing the correct label, i.e. 1.1.

Hope you can help.

Jake

[jakethepeguk1]

No worries all,

I have found the solution to my problem. You need to use the amsmath package, with the \tag function, which can tag new equations with previous labels.

Code: Select all

\usepackage{amsmath}
...
\begin{equation}
  y=mx+c
  \label{eqn1}
\end{equation}

As previously stated
\begin{equation}
  y=mx+c
  \tag{\ref{eqn1}}
\end{equation}

[Stefan Kottwitz]

Hi Jake,

nice to see that it's solved. And thanks for sharing the solution!
It would be great if you mark the question as solved then. This helps us to see the still open questions. Just edit your first post in this thread (the question) and choose the checkmark symbol as topic icon.

Stefan