When I have equations, as in
\begin{equation} ... \end{equation}
Can I arbitrarily assign the numbers to the equations? Instead of the usual order (1), (2), (3), …, I'd like something like (1), (2.1), (2.2), (2.3), (3.1), (3.2), (4), …
[Tex/LaTex] Label equations arbitrarily
equationslabels
Related Solutions
don't use \eqref. just use \ref. the main purpose of \eqref is to put parens around tags in accordance with ams style. it also ensures that they're set in upright type, which is not done with \ref, so you may still want to apply \upshape or \textup, although that isn't a problem as long as you are explicitly treating the tag as math.
Addendum: you can just equate \myeqref to \ref so that references to the explicitly-tagged displays can easily be found:
\newcommand\myeqref[1]{\ref{#1}}
although it's possible to adapt the amsmath definition to do what you want, it's more than i have time to unravel just now, especially when there's a simpler approach.
You can use empheq together with amsmath and its subequations environment.
\documentclass{book}
\usepackage{amsmath,empheq}
\usepackage{hyperref}
\begin{document}
\begin{subequations}\label{eq:system}
\begin{empheq}[left=\empheqlbrace]{align}
&\frac{d\psi}{d\zeta} = \frac{m_1}{y_1'}(x_1-\beta y_1') \label{eq:dpsidz}
\\
&\frac{dx_i}{d\zeta} = \frac{m_i}{\psi y_i'}(x_i-y_i')(x_i-\beta y_i')
\qquad \forall i=1,\dots,C-1 \label{eq:dxdz}
\\
&0 = y_1' (x_j-\beta y_j')-\alpha_{1j}y_j'(x_1-\beta y_1')
\qquad \forall j=2,\dots,C \label{eq:algeb1}
\\
&0 = \sum_{i=1}^{C}y_i' -1 \label{eq:algeb2}
\\
&\psi|_{\zeta=0} = 1
\\
&x_i|_{\zeta=0} = x_i^F \qquad \forall i=1,\dots,C
\end{empheq}
\end{subequations}
The system illustrated in \ref{eq:system} is a \textsc{dae} system
with a differential index equal to~$1$.
\end{document}
With hyperref the anchor will be immediately above the system.
A couple of stylistic notes:
- instead of
...you should input\dots; - instead of
\primeyou should use^{\prime}or the easier'(apostrophe) as in the code above.
Best Answer
Yes, absolutely, using the
amsmathpackage and its\tagcommand.A little example
After reading your comment, if you want the
equationnumber to inherit thetheoremnumber, then you can use, for example,and then you don't have to tag equations manually.