# sub-numeration using multlined

Hi I used multlined to produce this but I would like to get a sub-numeration for each 3 equations for example 1.a, 1.b 1.c with correspondent labels.

here is the code

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{amsmath,mathtools,relsize}
\begin{document}

$$\begin{multlined}[.7\textwidth] U_{shock}= + \mathlarger{\frac{\gamma-1}{2}}\\[5pt] \shoveleft{U_{rare}=-\frac{2c_{II}}{\gamma-1}\left[ \-\left(\frac{p_I}{p_{II}}\right)^{\frac{\gamma-1}{2\gamma}}\right]=F(p_I)\,;}\\[5pt] \shoveleft{U_{vac}=\frac{2(c_I+c_{II})}{\gamma-1}=F(0)\,.}\\[5pt] \end{multlined}$$

\end{document}


In my case, as I said I would like to have a numeration like (3.7a) (3.7b) (3.7c)

Tks!

• I edited your question to put the code in a code environment, and to provide an example that everyone could compile. – Clément Jul 2 '14 at 10:47

I think multlined is of no use here.

You can "hard-wire" the labels (or tags) you want with the \tag command:

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{amsmath,mathtools,relsize}
\begin{document}

\begin{align}
U_{shock}= + \mathlarger{\frac{\gamma-1}{2}} \tag{3.7a}\\
\shoveleft{U_{rare}=-\frac{2c_{II}}{\gamma-1}\left[ \-\left(\frac{p_I}{p_{II}}\right)^{\frac{\gamma-1}{2\gamma}}\right]=F(p_I)\,;}  \tag{3.7b} \\
\shoveleft{U_{vac}=\frac{2(c_I+c_{II})}{\gamma-1}=F(0)\,.}  \tag{3.7c}
\end{align}

\end{document}


If you mant this tag to be "context-sensitive" (i.e. if this equation moves to section 4, you want them to be tagged with 4.7.a, etc.), you should probably have a look at the mathtools package (p.9).

• You should really accept Bernard 's answer, which is more adapted and meaningful. – Clément Jul 2 '14 at 20:56

You don't need either multlined or \mathlarger: for the latter, it is enough to use \cfrac. Concerning subumbering, use the subequations environment. I rewrote the first line so as to have it like the image in the OP's question.

Two alignments are possible; I give them both in this code:

\documentclass{article}
\usepackage[utf8]{inputenc}

\usepackage{mathtools}

\begin{document}

\begin{subequations}
\begin{align}
U_\mathrm{shock} & = \frac{p_{II} - p_I}{\sqrt{\varrho_I \biggl[\cfrac{\gamma + 1}{2}\,p_{II} + \cfrac{\gamma - 1}{2}\, p_I\biggr]}} = F(p_{II}) \\[5pt]
U_\mathrm{rare} & =-\frac{2c_{II}}{\gamma-1}\left[\left(\frac{p_I}{p_{II}}\right)^{\frac{\gamma-1}{2\gamma}}\right]=F(p_I)\:;\\[5pt]
U_\mathrm{vac} & =\frac{2(c_I+c_{II})}{\gamma-1}=F(0).
\end{align}
\end{subequations}

With a different alignment:
\begin{subequations}
\begin{align}
&U_\mathrm{shock} = \frac{p_{II} - p_I}{\sqrt{\varrho_I\biggl[\cfrac{\gamma + 1}{2}\,p_{II} + \cfrac{\gamma - 1}{2}\, p_I\biggr]}} = F(p_{II}) \\[5pt]
&U_\mathrm{rare} =-\frac{2c_{II}}{\gamma-1}\left[ \left(\frac{p_I}{p_{II}}\right)^{\frac{\gamma-1}{2\gamma}}\right]=F(p_I)\:;\\[5pt]
&U_\mathrm{vac} =\frac{2(c_I+c_{II})}{\gamma-1}=F(0).
\end{align}
\end{subequations}

\end{document}