# Multiple labels for a single equation

I have an equation that looks like

y=4x \text{ for } x\in \{1,2\}


and would like to label it equation (1-2) so that the next equation in the paper is automatically labeled equation (3).

How can I do that?

• Welcome to TeX.SE. I hope you'll be comfortable with us all. Mar 29 '19 at 20:08

\documentclass{article}

\usepackage{amsmath}

\begin{document}

aaa \refstepcounter{equation}
$$1=0 \tag{\theequation--\the\numexpr\value{equation}+1\relax}$$

bbb\refstepcounter{equation}
$$0 =1$$
\end{document}


If you don't must to use sections, chapters, sub-sections, etc., a simple and fast solution it is uses a manual \tag for the first equation and automatic enumerate for other equations.

\documentclass[a4paper,12pt]{article}
\usepackage{mathtools}
$$x^2+y^2=4$$
$$\cos x +\sin x =1$$