I'd like to number multiline equations and reference them, à la MathJax's Align and Gather environments. Can this be accomplished? If so, how?
2 Answers
In the align environment, I use \tag
to number. \label
is also supported by MathJax. \ref
can be used to reference a line using \label
and \tag
.
For example: $$ \int_{-\infty}^\infty e^{-\pi x^2}\,\mathrm{d}x=1\label{a}\tag{1} $$ and reference it here: $\ref{a}$
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$\begingroup$ Thank you. Why is it that when I use \label in the align environment, the equations don't display but rather the underlying mathjax code? $\endgroup$– Evan AadApr 8, 2014 at 21:32
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7$\begingroup$ @EvanAad: There seems to be a problem when editing. I find that when I save the edit and reload the page, things look okay. The same thing happened while I was editing my answer. $\endgroup$– robjohn ModApr 8, 2014 at 21:33
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1
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5$\begingroup$ But how was this done? I can't edit this answer, so I can't see the source code. $\endgroup$ Dec 2, 2017 at 15:11
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4
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$\begingroup$ In the displayed equation you use \tag{1}. To refer to it you use \ref{a}. How does this work? I am not able to refer to \tagged equations. Am I missing the relevant part of MathJaX code? $\endgroup$– wdacdaOct 5, 2020 at 5:45
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$\begingroup$ @wdacda: The
\label{a}
is what is referenced by the\ref{a}
which is displayed as $\ref{a}$. $\endgroup$– robjohn ModOct 5, 2020 at 6:13 -
$\begingroup$ @robjohn I get it now! With \tag{1} we control what will show as the "name" of the equation. We need the label to use it in \ref. Wonderful! I was quite slow. But better ever, then never. I prefer using \eqref, it is more like in math texts. Thank you! $\endgroup$– wdacdaOct 5, 2020 at 7:01
In order to see the tags during edit, the following trick can be used.
$$ \begin{aligned} a & = b & (1) \\ c & = d & (2) \end{aligned} $$
But now the equations cannot be hyperlinked to.