How can I split an equation over two (or more) lines
Use either breqn to break lines automatically or use amsmath and its many environments exactly for this purpose. For example, with breqn:
\documentclass{article}
\usepackage{breqn}
\begin{document}
\begin{dmath}
Q(\lambda,\hat{\lambda}) = -\frac{1}{2} P{(O \mid \lambda )} \sum_s \sum_m \sum_t \gamma_m^{(s)} (t) \left( n \log(2 \pi ) + \log \left| C_m^{(s)} \right| + \left( \mathbf{o}_t - \hat{\mu}_m^{(s)} \right) ^T C_m^{(s)-1} \left(\mathbf{o}_t - \hat{\mu}_m^{(s)}\right) \right)
\end{dmath}
\end{document}
Note, the expression around \mid
required braces to prevent it from breaking at this point; I'm sure there is a better way to do that; anyway, here's the output:
With amsmath, you need to specify the break points manually: (as others have also mentioned)
\usepackage{amsmath}
...
\begin{multline}
A+B+C+ \\ +D+E+F
\end{multline}
The users guide to amsmath is called amsldoc.pdf, but you can access it by typing texdoc amsmath
on the command line. The main environments you'll use there would be align
, split
, and multline
.
You can use multline
or split
provided by amsmath
package.
- Use
multline
to split equations without alignment (first line left, last line right) - Use
split
to split equations with alignment
Here are examples:
The corresponding source code is as follows:
(i).Use equation:
\begin{equation}
1+2+3+4+8x+7=1+2+3+4+4x+35 \\
\Rightarrow x=7
\end{equation}
(ii).Use \emph{multline} to split equations without alignment:
\begin{multline}
1+2+3+4+8x+7=1+2+3+4+4x+35 \\
\Rightarrow x=7
\end{multline}
(iii).Use \emph{split} to split equations with alignment
\begin{equation}
\begin{split}
1+2+3+4+8x+7 & =1+2+3+4+4x+35 \\
& \Rightarrow x=7
\end{split}
\end{equation}
For more info, you can refer to User’s Guide for the amsmath Package.
First line left, last line right—that is the multline
environment:
\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{multline}
Q(\lambda,\hat{\lambda}) = -\frac{1}{2} P(O \mid \lambda ) \sum_s \sum_m \sum_t \gamma_m^{(s)} (t) \biggl( n \log(2 \pi ) \\
+ \log \left| C_m^{(s)} \right| + \left( \mathbf{o}_t - \hat{\mu}_m^{(s)} \right) ^T C_m^{(s)-1} \left(\mathbf{o}_t - \hat{\mu}_m^{(s)}\right) \biggr)
\end{multline}
\end{document}