I need something like this:
\left\{
first line (1a)
second line (1b)
third line (1c)
\right.
all lines should be aligned to left
[Tex/LaTex] subequations and array in braces
bracesnumberingsubequations
Related Solutions
If you want the middle column to be centered than you need to either resort to using a \makebox to reserve enough width for that column, which requires knowing what the widest element is beforehand, or to use an array:
Notes
- The
alignatprovides pairs ofrlaligned equations. Since we want the third column to beleft aligned, we need to use a&&to skip past the prior column that would have beenright aligned. - For the
arraysolution we need to use{}to make the inequality symbols be treated as relational operators, similar to the difference in spacing of$-x$and${}-x$. - The
calcpackage was used for the\widthof{}macro, so is only required for thealignatsolution. - As Qrrbrbirlbel commented, you could make use of the
arraypackage and incorporate the required{}into the column specification, as shown in the last example in the code below.
Code:
\documentclass{article}
\usepackage{amsmath}
\usepackage{calc}
\usepackage{array}
\newcommand*{\Widest}{effff}%
\newcommand*{\WideAs}[1]{\makebox[\widthof{$\Widest$}][c]{$#1$}}%
\begin{document}\noindent
You can use \verb|alignat|:
%
\begin{alignat*}{3}
a & \le \WideAs{b} && \le c \\
d & \le \WideAs{effff} && \le f
\end{alignat*}
%
Or use \verb|array|:
%
\[\begin{array}{r@{}c@{}l}
a \le {}& b &{} \le c \\
d \le {}& effff &{} \le f
\end{array}\]
%
Alternatively using the \verb|array| package:
\[\begin{array}{r<{{}}@{}c@{}>{{}}l}
a \le & b & \le c \\
d \le & effff & \le f
\end{array}\]
\end{document}
mathtools provides the multlined "subenvironment", which shifts the first line left,
the last line right, and applies only one number to each subequation.
put multiple multlined subequations together with gather:
\documentclass{article}
\usepackage{mathtools}
\begin{document}
\noindent X\hrulefill X\ignorespaces
\begin{subequations}
\label{energy13}
\begin{gather}
\begin{multlined}
u_e\frac{\partial \left(\varrho_e u_e\right)}{\partial t}
+ u_e\frac{\partial \left(\varrho_e u_e^2\right)}{\partial s}
+ u_e\frac{\partial \left(\varrho_e u_e v_e\right)}{\partial n}
-2 \varrho_e \varOmega u_e v_e \\
=- u_e\frac {\partial p_e}{\partial s}
+\qquad
+\varrho_e u_e\left(\varOmega^2R_{OPs}+\frac{\partial\varOmega}{\partial
t}(R_{OPn}+n)-\frac{\partial^2 R_{Os}}{\partial t^2}\right)
\end{multlined}
\\
\begin{multlined}
u\frac{\partial \left(\varrho u\right)}{\partial t}
+ u\frac{\partial \left(\varrho u^2 \right)}{\partial s}
+ u\frac{\partial \left(\varrho u v \right)}{\partial n}
-2 \varrho \varOmega u v \\
=- u\frac {\partial p}{\partial s}
+\mu u\frac {\partial^2 u}{\partial n^2}
+\varrho u \left(\varOmega^2R_{OPs}+\frac{\partial\varOmega}{\partial
t}(R_{OPn}+n)-\frac{\partial^2 R_{Os}}{\partial t^2}\right)
\end{multlined}
\end{gather}
\end{subequations}
\end{document}
the equation numbers are centered vertically on the subequations, rather than being set on the last line -- that's how all the "subenvironments" work.
Best Answer
(Update according to egreg's commend. Thanks!)
The first example of empheq given by Bernard is invalid if omitting the overload option when loading empheq package. For the latex file provided by Bernard, it has no problems at all. However, when I used
\usepackage[overload]{empheq}in IEEEtrans with a lot other packages loaded, it will freeze thepdflatexon my computer, I cannot see why, so I loaded it withoutoverloadoption. Here is the version when loadingempheqwithoutoverloadoption (\empheqlbraceis the big left parenthesis.\,is just used to add extra space; the default is too tight.):whose output looks like:
For a question on citations, it works out of box, e.g. see the following codes:
which gives