Split parts of an equation over two lines

equations

I have a question concerning equations in Latex. Let's assume there is a simple piecewise function as below (the actual one has terms which are much longer):

As each line runs on for quite a bit, I would like to split the selector over two lines however still aligned with the case. Is this possible?

\begin{equation}
    \label{eqn:c(n)}
    {
        c(n) = \begin{cases}
            f(x)), & $if n=0 where x=1$ \\[1em]
            f(x), & $if n\textgreater0 where x=c(n-1)+n$ \\
        \end{cases}
    }
\end{equation}

This is what I have so far.

Best Answer

I would like to suggest that you employ a cases environment (provided by the amsmath package) and embed in it two array environments.

\documentclass{article} % or some other suitable document class
\usepackage{amsmath}    % for 'cases' environment
\usepackage{booktabs}   % for '\addlinespace' macro

\begin{document}
\[
C(n)=
\begin{cases}
f(x), & \begin{array}{@{}l@{}}
          n=0\\
          \text{where $x=1$} 
        \end{array} \\ \addlinespace % increase the vertical separation
f(x), & \begin{array}{@{}l@{}}
          n>0\\
          \text{where $x=c(n-1)+n$}
        \end{array}
\end{cases}
\]
\end{document}

Related Solutions

[Tex/LaTex] How to 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:

rendered

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.

[Tex/LaTex] How to split optimisation problem over two lines

If you need to break up the conditions of the minimization problem across two or more lines, the following will work:

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{equation*}
  \min_{\substack{A,B\\ 0\le A\le T \\ 
     D+X+W-S\ge 0}}
  \Bigl(I+X+W-E-\bigl(X+k(A-B)\bigr)\Bigr)
\end{equation*}
\end{document}

enter image description here

If you want the minimization conditions to be spread over just two lines, replace the first \\ with ;\ and you'd get:

enter image description here

Addendum, posted after receiving a clarification from the OP: If, rather, the objective is to break up the argument of the minimization problem (I must confess I'd overlooked the comma in the earlier MWEs), the following should be of interest:

\documentclass{article}
\usepackage{mathtools}
\setlength\textwidth{2in} % simulate a narrow column
\begin{document}
\begin{multline*}
  \min_{\mathclap{\substack{A,B\\ 0\le A\le T \\ D+X+W-S\ge 0}}}
     \big(I+X+W-E,\\[-5ex]
     X+k(A-B)\big)
\end{multline*}
\end{document}

enter image description here

Best Answer

Related Solutions

[Tex/LaTex] How to split an equation over two (or more) lines

[Tex/LaTex] How to split optimisation problem over two lines

Related Question