I have a problem similar to this question.
I want to typeset k
equations with the horizontal \dots
and the \vdots
aligned. The problem is that I want the equations to be aligned to the opening brace.
For example the following code:
\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{equation}
\left\lbrace %
\begin{split}
a + b + &\dots + c = d \\
a + b + &\dots + c = d \\
&\setbox0\hbox{=}\mathrel{\makebox[\wd0]{\vdots}} \\
aaaaaaa + b + &\dots + c = d
\end{split} %
\right.
\end{equation}
\end{document}
Produces:
As you can see the first two equations start far from the brace. So I tried this:
\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{equation}
\left\lbrace %
\begin{split}
&a + b + &\dots + c = d \\
&a + b + &\dots + c = d \\
& &\setbox0\hbox{=}\mathrel{\makebox[\wd0]{\vdots}} \\
&aaaaaaa + b + &\dots + c = d
\end{split} %
\right.
\end{equation}
\end{document}
That yields what I want, but the vertical dots are not centered under the horizontal dots:
How can I obtain the alignment as in the second image but with the vertical dots aligned as in the first example?
Best Answer
In this case
split
is not the best choice; rather usearray
:With the addition of
<{{}}
an empty object is inserted so that the spacing around the operation symbols is correct.You can also simplify the input by adding another alignment point:
(Notice the use of
\dotsb
in this case, to get the right dots.)