Fit equation with \cases in page width using \resizebox

casesequationsresizetextwidth

I'm trying to fit an equation with several cases into my page width. The pain is that one case is awfully long. I used the \resizebox{} approach (see solution here), which would work, if there would be no \begin{cases}.

I learned that \resizebox creates a 'new' box and within this box there is no math environment, which is the reason why the solution math content starts with an $, to trigger the inline math mode. My problem is that \begin{cases} is not suitable for the inline math mode, and I receive a 'Missing $ inserted.' error.

Do you have an alternative approach to solve this issue. Adding another \begin{equation} within the box does not work. The work compiles but I would love to see a smoother solution than latex putting $ by itself. – Thanks!

Code looks like this:

\begin{equation}
\resizebox{.9\hsize}{!}{
  r(b_{i,t}^C,p_{market,t})= \begin{cases}  
    -(b_{i,t}^C - p_{market,t})^2,      & \text{if} b_{i,t}^C > p_{market,t}\\
    -(b_{i,t}^C - p_{grid})^2,          & \text{if} b_{i,t}^C < p_{market,t} \\
    \frac{p_{market,t}}{100} + \theta,  & \text{if} b_{i,t}^C = p_{market,t} \\
    \frac{p_{market,t}}{100} + 2\theta, & \text{if} b_{i,t}^C = p_{market,t} \text{and} b_{i,t}^C < min(b_{i,t-j}^C,.., b_{i,t-1}^C) \quad|  b_{i,t-j}^C=p_{market,t-j} 
 \end{cases}
 }
\end{equation}

Best Answer

You can split the long condition into three lines.

\documentclass{article}
\usepackage{amsmath}

\begin{document}

\begin{equation}
  r(b_{i,t}^C,p_{\mathrm{market},t})=
  \begin{cases}  
    -(b_{i,t}^C - p_{\mathrm{market},t})^2,
      & \text{if } b_{i,t}^C > p_{\mathrm{market},t} \\[2ex]
    -(b_{i,t}^C - p_{\mathrm{grid}})^2,
      & \text{if } b_{i,t}^C < p_{\mathrm{market},t} \\[2ex]
    \frac{p_{\mathrm{market},t}}{100} + \theta,
      & \text{if } b_{i,t}^C = p_{\mathrm{market},t} \\[2ex]
    \frac{p_{\mathrm{market},t}}{100} + 2\theta,
      & \begin{aligned}[t]
        &\text{if } b_{i,t}^C = p_{\mathrm{market},t} \text{ and} \\
        &b_{i,t}^C < \min(b_{i,t-j}^C,\dots, b_{i,t-1}^C) \\
        &\mid b_{i,t-j}^C=p_{\mathrm{market},t-j}
        \end{aligned}
  \end{cases}
\end{equation}

\end{document}

Note \mathrm{market}, \mathrm{grid}, \dots and \min.

Related Solutions

[Tex/LaTex] Using “cases” inside “equation” gives error[with “amsmath” loaded]

In the displaymath mode, you can not use any paragraph triggering commands such as blank lines or \par commands. (Not a good idea, but you can use it inside the cases environment). Also you don't need to switch to text mode and then again to math mode. You can just use text on the text and leave the rest as it is.

Another point is the use of & characters which is the column delimiter that should be used inside the cases environment. This would be apparent if one of the cases starts with 1250 and the other is 1 which would lead to a bad alignment (try without the & characters!).

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{equation*}
X(\omega) = \begin{cases}
1 &\text{se $\omega\in A$}\\
1250 &\text{se $\omega \in A^c$}
\end{cases}
\end{equation*}

\end{document}

enter image description here

Also mathtoolspackage provides some nice extensions and bugfixes of amsmath, so here is an example of dcases* environment which automatically switches to text mode in the second entry of the case declaration:

\documentclass{article}
\usepackage{mathtools}
\begin{document}
\[
X(\omega) = \begin{dcases*}
1 & se $\omega\in A$\\
0 & se $\omega \in A^c$
\end{dcases*}
\]
\end{document}

enter image description here

If you are using the standalone class (which gives errors) then you have to use it as

\documentclass[preview]{standalone}

[Tex/LaTex] alignat with right curly bracket/cases spanning some but not all lines

I propose one of these layouts, with the drcases environment from mathtools:

\documentclass{article}
\usepackage{mathtools}

\begin{document}

\begin{align*} \psi^\star \mathcal{H} \; \psi = i \smash[b]{\sum_{h=(1,1,1)}^{(M,N,Z)}} ( &\\[-3.75ex]
                         & \! \begin{drcases}
    A1 \quad AAAAAAAAAA2 & A3 \\
    B1 \quad BBBBBBBBBB2 & B3 \\
    C1 \quad CCCCCCCCCC2 & C3 \\
    D1 \quad DDDDDDDDDD2 & D3 ).
    \end{drcases}\delta(\alpha-1)
  \end{align*}

  where I want to place a curly bracket to right of the last 4 lines and put the expression $\delta(\alpha-1)$ on the right of the bracket-tip.
  \begin{align*} \psi^\star \mathcal{H} \; \psi = i \sum_{\mathclap{h=(1,1,1)}}^{\mathclap{(M,N,Z)}} \,( \enspace \begin{drcases}
    A1 \quad AAAAAAAAAA2 & A3 \\
    B1 \quad BBBBBBBBBB2 & B3 \\
    C1 \quad CCCCCCCCCC2 & C3 \\
    D1 \quad DDDDDDDDDD2 & D3 ).
    \end{drcases}\delta(\alpha-1)
  \end{align*}

\end{document}

Best Answer

Related Solutions

[Tex/LaTex] Using “cases” inside “equation” gives error[with “amsmath” loaded]

[Tex/LaTex] alignat with right curly bracket/cases spanning some but not all lines

Related Question