[Tex/LaTex] How to put a box around a equation spreading multiple lines

alignboxes

I want to put a box around a equation spreading multiple lines.
Minimum working example:

 \documentclass{article}
 \usepackage[utf8]{inputenc}
 %\usepackage{amsmath}
 \usepackage{comment}
 \usepackage{mathtools, cuted}
 %\usepackage{natbib}
 \usepackage{amssymb}
 \usepackage{breqn}
 %\usepackage{amsthm}
 \usepackage{hyperref}
 %\bibliographystyle{plain}
 %\newtheorem{thm}{Theorem}[section]
 %\newtheorem{lem}[thm]{Lemma}
 %\newtheorem{cor}[thm]{Corollary}
 \newtheorem{rmk}{Remark}
 %\newtheorem{def}[rmk]{Definition}
 %\newtheorem*{proof}{Proof}
 \usepackage{amsmath}
 \usepackage{mathtools}
 \usepackage{enumitem}

  %\usepackage[dvips]{epsfig}    % or this line, depending on which
                           % you prefer.
  \makeatletter
  \DeclareRobustCommand{\qed}{%
  \ifmmode % if math mode, assume display: omit penalty etc.
  \else \leavevmode\unskip\penalty9999 \hbox{}\nobreak\hfill
  \fi
  \quad\hbox{\qedsymbol}}
  \newcommand{\openbox}{\leavevmode
  \hbox to.77778em{%
  \hfil\vrule
  \vbox to.675em{\hrule width.6em\vfil\hrule}%
  \vrule\hfil}}
  \newcommand{\qedsymbol}{\openbox}
  \newenvironment{proof}[1][\proofname]{\par
  \normalfont
  \topsep6\p@\@plus6\p@ \trivlist
  \item[\hskip\labelsep\itshape
  #1.]\ignorespaces
   }{%
  \qed\endtrivlist
  }
   \newcommand{\proofname}{Proof}
   \makeatother

   \begin{document}
   \begin{align}
    &\frac{1}{\min_i \sum_j e^{c(i,j)}p(j|i)}\sum_{i,j=1}^s                                      e^{c(i,j)}p(j|i)x_i y_j \left[c(i,j) + \ln p(j|i)-\ln \sqrt{\pi_i} - 
   \ln\phi^{k(i)}(i) -\ln\left(\sum_{l=1}^s \phi^{k(i)}(l)\pi_la_{lj}         \right)+\ln \sqrt{\pi_j}+ \right. \nonumber \\
   & \left. \ln\left(\sum_{m=1}^s{\phi^{k(i)}(m)}^2\pi_m\right)\right]        \label{first}.
   \end{align}
   \end{document}

Best Answer

Something like this?

 \documentclass{article}

\usepackage[margin=0.5in]{geometry}
\usepackage{empheq}


   \begin{document}
   \begin{empheq}[box=\fbox]{align}
    &\frac{1}{\min_i \sum_j e^{c(i,j)}p(j|i)}\sum_{i,j=1}^s                                      e^{c(i,j)}p(j|i)x_i y_j \left[c(i,j) + \ln p(j|i)-\ln \sqrt{\pi_i} - 
   \ln\phi^{k(i)}(i) -\ln\left(\sum_{l=1}^s \phi^{k(i)}(l)\pi_la_{lj}         \right)+\ln \sqrt{\pi_j}+ \right. \nonumber \\
   & \left. \ln\left(\sum_{m=1}^s{\phi^{k(i)}(m)}^2\pi_m\right)\right]        \label{first}.
   \end{empheq}
   \end{document}

Related Solutions

[Tex/LaTex] Box or [ around multiple lines inside align

An option using a \parbox inside a \fcolorbox inside a \makebox, and the whole construct inside \intertext; some changes to the original mark-up were done (in particular, the code was greatly simplified), but the original alignment of expressions before and after the box was preserved:

\documentclass{article}
\usepackage{mathtools}
\usepackage{tikzpagenodes}
\usetikzlibrary{tikzmark}

\begin{document}

Let:
\begin{align*}
G_{\delta_r}^{\beta} &= \frac{n_1 s + n_0}{s^2 + d_1 s + d_0} = \frac{0.01956 s + 7.01}{s^2 + 0.802 s + 6.489} \\
\text{step} \left(G_{\delta_r}^{\beta}(s) \right) = \frac{G_{\delta_r}^{\beta}(s)}{s} &= \frac{1}{s} \cdot \frac{n_1 s + n_0}{s^2 + d_1 s + d_0}
\intertext{%
\makebox[\linewidth][c]{\fcolorbox{blue}{white}{\parbox{\linewidth}{%
Expanding with partial fractions:
\[
\frac{x_1}{s} + \frac{x_{21}s + x_{20}}{s^2 + d_1 s + d_0} = 
\frac{1}{s} \cdot \frac{n_1 s + n_0}{s^2 + d_1 s + d_0}
\]
Removing denominator:
\[
x_1(s^2 + d_1 s + d_0) + s(x_{21} s + x_{20}) = n_1 s + n_0 
\]
Has solutions:
\[
x_{21} = \frac{-n_0}{d_0} = -1.08\qquad
x_1 = \frac{n_0}{d_0} = 1.08\qquad
x_{20} = n_1 - \frac{n_0 d_1}{d_0} = -0.847
\]
Hence:}}}
}
\frac{G_{\delta_r}^{\beta}(s)}{s} &= \frac{1.08}{s} - \frac{1.08s + 0.847}{s^2 + 0.8-2s + 6.489} \\
\shortintertext{Completing the square:}
\frac{G_{\delta_r}^{\beta}(s)}{s} &= \frac{1.08}{s} - \frac{1.08s + 0.847}{(s + 0.401)^2 + 6.328} \\
\shortintertext{Inverse Laplace:}
\mathcal{L}^{-1}\left\{ \frac{G_{\delta_r}^{\beta}(s)}{s} \right\} &=  1.08 - e^{-.401t} \left(1.08 \cos\alpha + \frac{0.847}{\sqrt{6.328}} \sin\alpha \right), 
\end{align*}
where $\alpha=t\sqrt{6.328}$.

\end{document}

enter image description here

Another option would be to use the tikzmark library; the idea is to use \tikzmark to place marks at the appropriate locations and then to use those marks to draw the blue rectangle. Below I show this approach and also illustrate another option for the mark-up (of course, this approach will also work with the above approach or with any other variation):

\documentclass{article}
\usepackage{mathtools}
\usepackage{tikzpagenodes}
\usetikzlibrary{tikzmark}

\begin{document}

Let:
\begin{align*}
G_{\delta_r}^{\beta} &= \frac{n_1 s + n_0}{s^2 + d_1 s + d_0} = \frac{0.01956 s + 7.01}{s^2 + 0.802 s + 6.489} \\
\text{step} \left(G_{\delta_r}^{\beta}(s) \right) = \frac{G_{\delta_r}^{\beta}(s)}{s} &= \frac{1}{s} \cdot \frac{n_1 s + n_0}{s^2 + d_1 s + d_0}
\end{align*}         
\tikzmark{start}Expanding with partial fractions:
\[
\frac{x_1}{s} + \frac{x_{21}s + x_{20}}{s^2 + d_1 s + d_0} = 
\frac{1}{s} \cdot \frac{n_1 s + n_0}{s^2 + d_1 s + d_0}
\]
Removing denominator:
\[
x_1(s^2 + d_1 s + d_0) + s(x_{21} s + x_{20}) = n_1 s + n_0 
\]
Has solutions:
\[
x_{21} = \frac{-n_0}{d_0} = -1.08\qquad
x_1 = \frac{n_0}{d_0} = 1.08\qquad
x_{20} = n_1 - \frac{n_0 d_1}{d_0} = -0.847\tikzmark{end}
\]
Hence:
\begin{align*} 
\frac{G_{\delta_r}^{\beta}(s)}{s} &= \frac{1.08}{s} - \frac{1.08s + 0.847}{s^2 + 0.8-2s + 6.489} \\
\shortintertext{Completing the square:}
\frac{G_{\delta_r}^{\beta}(s)}{s} &= \frac{1.08}{s} - \frac{1.08s + 0.847}{(s + 0.401)^2 + 6.328} \\
\shortintertext{Inverse Laplace:}
\mathcal{L}^{-1}\left\{ \frac{G_{\delta_r}^{\beta}(s)}{s} \right\} &=  1.08 - e^{-.401t} \left(1.08 \cos(t\sqrt{6.328}) + \frac{0.847}{\sqrt{6.328}} \sin(t\sqrt{6.328}) \right) 
\end{align*}

\begin{tikzpicture}[remember picture,overlay]
\draw[line width=1.5pt,blue]
  ([xshift=-1ex,yshift=2.5ex]current page text area.west|-{pic cs:start})
  rectangle
  ([yshift=-2.5ex]current page text area.east|-{pic cs:end});
\end{tikzpicture}

\end{document}

enter image description here

[Tex/LaTex] Box for multiple lines and automatic width

How about a simple tabular?

% arara: pdflatex
\documentclass{article}
\begin{document}

I like \begin{tabular}{l}A\\B\\C2\end{tabular} but who cares?
\end{document}

screenshot

Best Answer

Related Solutions

[Tex/LaTex] Box or [ around multiple lines inside align

[Tex/LaTex] Box for multiple lines and automatic width

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