[Tex/LaTex] long equation in two column paper (the mathtool doesnt work.)

equations

I have an equation which is too long for a two-column paper. the code that I write is like below :

\begin{equation*}
\begin{split}
J=\frac{\displaystyle -l_2}{\displaystyle sin(\theta_3-\theta_2)}\cdot
\begin{matrix}
sin(\theta_1)sin(\theta_3-\theta_2)+sin(\theta_2)sin(\theta_1-\theta_3)&-sin(\theta_2)sin(\theta_4-\theta_3)\\
-cos(\theta_1)sin(\theta_3-\theta_2)-cos(\theta_2)sin(\theta_1-\theta_3)&cos(\theta_2)sin(\theta_4-\theta_3)
\end{matrix}
 \end{split}
\end{equation*}

but it doesn't work.what can i do?

Best Answer

The best approach would be to introduce some new symbols such as Z=\sin(\theta_3-\theta_2) in order to get it easier to read and shorter to typeset.

Assuming that you need all those terms in one equation, you could possibly do like the following:

% arara: pdflatex

\documentclass[twocolumn]{article}
\usepackage{mathtools}
\usepackage{blindtext}

\begin{document}
\blindtext
    \begin{multline*}
        J=\frac{-l_2}{\sin(\theta_3-\theta_2)}\cdot \\
        \begin{bmatrix}
            \begin{split}&\sin(\theta_1)\sin(\theta_3-\theta_2)\\&\quad+\sin(\theta_2)\sin(\theta_1-\theta_3)\end{split}&-\sin(\theta_2)\sin(\theta_4-\theta_3)\\[3ex]
            \begin{split}&-\cos(\theta_1)\sin(\theta_3-\theta_2)\\&\quad-\cos(\theta_2)\sin(\theta_1-\theta_3)\end{split}&\cos(\theta_2)\sin(\theta_4-\theta_3)
        \end{bmatrix}
    \end{multline*}
\blindtext
\end{document}

enter image description here

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[Tex/LaTex] Splitting a long equation with a curly brace for the equations in two lines

I find the use of "\big and friends" to be a quick fix that works 99% of the time, with that 1% being quite frustrating to solve. I took Mico's answer (credit to him for the improved layout of the first two equations) and reverted back to the old trustworthy \left and \right pairs, where LaTeX decides how to stretch/extend the extensible delimiters () and {}. There is problem when stretching has to occur across more than one line in an equation though. But for that, \vphantom{...} allows a vertical (zero-width) stretch of the correct height. By example, here's my code:

\documentclass{article}
\newcommand{\Cbar}{\overline{C}}
\newcommand{\Dbar}{\overline{D}}
\newcommand{\myfrac}{\dfrac{\partial^{2}w}{\partial x^{2}}}% For height purposes
\usepackage{amsmath}

\begin{document}
\begin{subequations}\label{e34} 
\noindent
The Normal Stress $q$ is given by 
\begin{align}
\begin{split}
q = &\phantom{=} \Cbar_1\Cbar_3\Cbar_5\dfrac{\alpha^{*}k_s w}{U\left(1+ \alpha^{*}k_s 
(w/q_u)\right)}
- \myfrac\left\{\vphantom{\myfrac}G_1 H_1+\Cbar_2(T_p+T_1)\cos\theta \right.
\label{e34a}\\
&+G_2 H_2\Cbar_1+ G_3 H_3 \Cbar_1 \Cbar_3+G_4 H_4 \Cbar_1 \Cbar_3\Cbar_5 \\
&+\>\Cbar_1\Cbar_4(T_p+T_2)\cos\theta+\Cbar_1\Cbar_3\Cbar_6(T_p+T_3)\cos\theta
\left.\vphantom{\myfrac}\!\right\}\,.\\
\end{split}
\intertext{The Mobilised Tension for top reinforcement is}
\begin{split}
\frac{\partial T_1}{\partial x} 
= & -\bigg(q+G_1H_1\frac{\partial^{2}w}{\partial x^{2}}\bigg)\  \Dbar_1 \\
&- \bigg(\Cbar_3\Cbar_5\dfrac{\alpha^{*}k_s w}{U\big(1+\alpha^{*}k_s(w/q_u)\big)} 
- A_1 \frac{\partial^{2}w}{\partial x^{2}}\bigg)\  \Dbar_2\\
\end{split}
\intertext{The Mobilised Tension for middle reinforcement is}
\begin{split}
\frac{\partial T_2}{\partial x} 
= & -\left(\frac{1}{\Cbar_1} 
\left(q+A_2\frac{\partial^{2}w}{\partial x^{2}} \right) 
+G_2 H_2\frac{\partial^{2}w}{\partial x^{2}} \right)\ \Dbar_3  \label{e34c} \\
&- \left( \Cbar_5 \dfrac{\alpha^{*}k_s w}{U\left(1+\alpha^{*}k_s(w/q_u)\right)} 
- A_3 \dfrac{\partial^{2}w}{\partial x^{2}} \right)\ \Dbar_4\\
\end{split}
\intertext{The Mobilised Tension for bottom reinforcement is}
\begin{split}
\frac{\partial T_3}{\partial x} 
= & -\left(\frac{1}{\Cbar_3}\left(\frac{1}{\Cbar_1}\left(q+A_2\frac{\partial^{2}w}
{\partial x^{2}} \right)
+A_4\frac{\partial^{2}w}{\partial x^{2}}\right)+G_3 H_3\frac{\partial^{2}w}{\partial
x^{2}} \right)\ 
\Dbar_5  \label{e34d} \\
&-\left( \dfrac{\alpha^{*}k_s w}{U\left(1+\alpha^{*}k_s(w/q_u)\right)} - G_4H_4 
\frac{\partial^{2}w}{\partial x^{2}} \right)\ \Dbar_6 \\
\end{split}
\end{align}
\end{subequations}

\end{document}

Multiple equations that are split with extensible delimiters

The macro \newcommand{\myfrac}{\dfrac{\partial^{2}w}{\partial x^{2}}} is introduced just for the sake of brevity.

For more ideas on how to work with math in LaTeX, Herbert Voss' mathmode document is an invaluable source.

[Tex/LaTex] Long equation in two column paper

You could use the \splitrule macro of the mathtools package to split the numerator term into two parts. In the example below, that's what's done in the first equation. In the second equation, I suggest applying a few more modifications; adopt them as you see fit.

enter image description here

\documentclass[a4paper,twocolumn]{article}
\usepackage{mathtools}
\begin{document}
With just \texttt{\textbackslash splitrule} applied:
\begin{equation}\label{simpleRule}
    \frac{\splitfrac{S=<R,A,O>, P\in AFP (O),}
           { <R,A,P,E>\in Observed}}
        {S\models \diamondsuit E}
\end{equation}
With a few more modifications applied:
\begin{equation}\label{notsosimpleRule}
    \frac{\splitfrac{S=\langle R,A,O\rangle, P\in \textit{AFP} (O),}
           { \langle R,A,P,E \rangle \in \textit{Observed}}}
        {S\models \diamondsuit E}
\end{equation}
\end{document}

Finally, I can't help but comment on the fact that the letters in the second angle-brackets expression make for an extremely unpleasant -- and very likely utterly distracting -- word. Any chance you can come up either with a different ordering of the four letters or an entirely different set of four letters?

Best Answer

Related Solutions

[Tex/LaTex] Splitting a long equation with a curly brace for the equations in two lines

[Tex/LaTex] Long equation in two column paper

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