# Manually numbering an equation in Beamer

Similar to an old 2011 posting here, I would like to manually tag a particular line of equation with number in Beamer. I tried using \tag{} command but it does not work, putting in \usepackage{amsmath} also does not help. I am working under these environments:

\documentclass{beamer}
\mode {
\usetheme{Ilmenau}
\usecolortheme{beaver}}


And here is a compilable example from my slides:

$x = r \cos \theta \tag{1}$.

Here, ShareLatex ignores \tag{1} but compiles the rest of the equation correctly.

PS.: I do not have any need to reference the tagged equation later.

• Could you please provide a compilable minimal working example? – Herr K. Apr 24 '15 at 19:53
• @HerrK. Thanks for your suggestion. See the above for compilable example. Thanks again. – Amanda.M Apr 24 '15 at 20:32
• Welcome to TeX.SX! Please make your code compilable (if possible), or at least complete it with \documentclass{...}, the required \usepackage's, \begin{document}, and \end{document}. That may seem tedious to you, but think of the extra work it represents for TeX.SX users willing to give you a hand. Help them help you: remove that one hurdle between you and a solution to your problem. A tip: You can use backticks  to mark your inline code as I did in my edit. – adn Apr 24 '15 at 20:45

After a small correction of (first version of) your code:

\documentclass{beamer}

\usetheme{Ilmenau}
\usecolortheme{beaver}

\begin{document}

$$1+1=2$$

$$1+1=2 \tag{mytag}$$

\end{document}


The source of your problem seems to be inline formula, i.e. between dollar signs, not inside, say, equation environment.

• Thank you! Let me work on it and will get back with you if there is still any issue. Thanks again. – Amanda.M Apr 24 '15 at 21:48
• I am not sure I understand your last comment. Did you say that \tag{ } can not be used between dollar signs? Since I have to use dollar signs, what should I do to manually number an equation? Thanks again. – Amanda.M Apr 25 '15 at 11:33
• @A.Magnus Using \tag simply between dollars your should obtain amsmath error \tag not allowed here. Your \tag should be in a place, where the behaviour is as between double dollars, e.g. $2\tag{second}$`. – Przemysław Scherwentke Apr 26 '15 at 17:58