[Tex/LaTex] Coloured equation number (without changing colour of reference using hyperref)

colorequationshyperref

I am working on a file where I am using the package hyperref so that the references to equations are linked and coloured. Here is a MWE:

\documentclass{article}
\usepackage{amsmath}
\usepackage{hyperref}
\hypersetup{colorlinks=true}

\begin{document}

\begin{equation}
1=\beta\left[ \frac{ 1+\left( 1-\tau_{t+1}\right) r_{t} }{\Pi_{t+1}} \right]\label{Fisher}
\end{equation}

Make reference to \eqref{Fisher}.

\end{document}

This gives me the reference at the end red, which is great. Now I want to have the equation number in blue (not the reference to the equation, but the equation number itself). I achieve that by adding

\renewcommand\theequation{{\color{blue}\arabic{equation}}}

to the preamble, before of after hyperref (the result seems to be the same). On first compile, great, I get the exact result I want: the equation number is blue, and the reference to the equation is in red:

enter image description here

but a second compile will turn both the equation number and the reference to the equation blue!

How can I avoid that, and have my equation number in blue not interfere with the equation reference colour from hyperref?

Best Answer

You can adapt this answer by Andrew Stacey

\documentclass{article}
\usepackage{amsmath}
\makeatletter
\let\reftagform@=\tagform@
\def\tagform@#1{\maketag@@@{(\ignorespaces\textcolor{blue}{#1}\unskip\@@italiccorr)}}
\renewcommand{\eqref}[1]{\textup{\reftagform@{\ref{#1}}}}
\makeatother
\usepackage{hyperref}
\hypersetup{colorlinks=true}

\begin{document}

\begin{equation}
1=\beta\left[ \frac{ 1+\left( 1-\tau_{t+1}\right) r_{t} }{\Pi_{t+1}} \right]\label{Fisher}
\end{equation}

Make reference to \eqref{Fisher}.

\end{document}

Related Solutions

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I would definitely go the second way with $\displaystyle: I find that it looks strange to have something centered after a bullet. To get the vertical alignment correct, just add [t] after \begin{aligned}, where "t" means "top". (See also the top of page 8 of the User's guide for the amsmath Package.)

[Tex/LaTex] List of equations, including equation contents and caption

Since you want a cheat sheet, I'd recommend the extract package. With a slightly different MWE:

\documentclass{article}
\usepackage[
  active,
  header=false,
  copydocumentclass=true,
  generate=\jobname-Cheatsheet,
  extract-env={equation},
  extract-cmdline={synopsis},
  ]{extract} % http://ctan.org/pkg/extract
\begin{extract*}
% Items executed in both the main and extracted document
% (extract manual, section 5.1)
\usepackage{amsmath}
\end{extract*}
\begin{extract}
% Items executed only in extracted document
\def\synopsis#1{#1}
\end{extract}
\def\synopsis#1{}
\begin{document}
First Euler observed that
\synopsis{Euler's equation tying together the five fundamental constants of mathematics}%
\begin{equation}
1 + e^{i \Pi} = 0.
\end{equation}

Then, Gauss discovered the normal distribution:
\synopsis{Normal distribution}%
\begin{equation}
P(x) = \frac{1}{{\sigma \sqrt {2\pi } }}e^{{{ - \left( {x - \mu } \right)^2 } \mathord{\left/ {\vphantom {{ - \left( {x - \mu } \right)^2 } {2\sigma ^2 }}} \right. \kern-\nulldelimiterspace} {2\sigma ^2 }}}
\end{equation}

Finally, Einstein proclaimed: 
\synopsis{Equivalence of mass and energy}%
\begin{equation}
E = m C^2
\end{equation}
\end{document}

you get an original document of:

enter image description here

and an extracted document of:

\documentclass{article}
% Items executed in both the main and extracted document
% (extract manual, section 5.1)
\usepackage{amsmath}
% Items executed only in extracted document
\def\synopsis#1{#1}

\begin{document}

\synopsis{Euler's equation tying together the five fundamental constants of mathematics}%

\begin{equation}
1 + e^{i \Pi} = 0.
\end{equation}

\synopsis{Normal distribution}%

\begin{equation}
P(x) = \frac{1}{{\sigma \sqrt {2\pi } }}e^{{{ - \left( {x - \mu } \right)^2 } \mathord{\left/ {\vphantom {{ - \left( {x - \mu } \right)^2 } {2\sigma ^2 }}} \right. \kern-\nulldelimiterspace} {2\sigma ^2 }}}
\end{equation}

\synopsis{Equivalence of mass and energy}%

\begin{equation}
E = m C^2
\end{equation}

\end{document}

and:

enter image description here

This also works with your original \caption command.

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