Can I make a footnote to clarify an important point inside an equation?
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5any problem in trying it yourself or is it a general question about the sense?– user2478Jan 22, 2014 at 22:29
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1There is no link to the footnote but there exists no footnote.– VesnogJan 22, 2014 at 23:02
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Related Question: Footnote in align enviroment.– Peter GrillJan 23, 2014 at 5:17
1 Answer
First: think carefully whether that is the right thing to do, then don't do it. Most symbols for footnote marks can have a mathematical meaning. I once spent several minutes wondering about the meaning of a mathematical expression before I deduced that one of the exponents had to be a footnote mark. My preferred methods of explaining parts of an equation are to explain it in words either before or after the equation, or within the equation as a comment:
\documentclass{article}
\begin{document}
In the following expression, $q$ is required to be an integer:
\[
n = q\cdot k
\]
And here is another equation:
\[
a^2 + b^2 = c^2 \qquad\text{($c$ is required to be an integer.)}
\]
\end{document}
If one really must have a footnote, you can just try the \footnote
command. This can fail in some circumstances, in which case one can use the pair of commands \footnotemark
and \footnotetext
, the latter outside the math environment:
\documentclass{article}
\usepackage{amsmath}
\begin{document}
Plain footnote works:
\[
X^2 = Y\footnote{$Y$ is a matrix}
\]
Need to separate mark and text:
\begin{align}
X^2 &= Y\footnotemark\\
Y^2 &= Z
\end{align}\footnotetext{$Y$ is a matrix}
\end{document}
Unfortunately, it can happen that the \footnotetext{...}
ends up on the next page.
I don't know a simple means to prevents that, except to move it before the math environment when it happens.