I am trying to label several lines at once in a very long equation. From this question I have come up with the following minimal example:
\documentclass{report}
\usepackage[onehalfspacing]{setspace}
\usepackage{amsmath}
\begin{document}
\begin{align*}
x &= \sum_i c_i X_i \\
&\left. \def\arraystretch{1.5}
\begin{array}{l}
+ \sum_i c_i Y_i \\
+\sum_i c_i Z_i
\end{array}
\right\} \tag{From (1)} \\
\end{align*}
\end{document}
which generates
As you can see I have attempted to correct the fact that array by default will have smaller row spacing than the align*. However, I cannot make the font sizes match up and the line spacing is really not that good either. I have tried using begingroup, endgroup but that doesn't seem to work. I would really appreciate any help on this!
Best Answer
If I have understood your problem correctly, you can make use of
mathtools
'drcases
environment (d
stands for displaystyle, whiler
means the brace will be on the right):If you want more space between the math and the brace, you can add
\quad
(or any other space) to the end of the longest line:Another possibility (less "automatic") is to give the extra linespacing in square brackets after the
\\
as in\\[.5em]
, which will give an extra 0.5 em of linespacing after the line you are ending.