Text Formatting ⇒ Equation on multiple lines

[minidiable]

Hi to everyone, I am writing a journal article for the IOP Smart Materials and Structures.

I wrote this equation:

Code: Select all

\begin{equation}
\begin{multlined}
\frac{dW}{d\lambda} = \sigma_{1}-\sigma_{2}\nonumber
 = nk\Theta\times\Biggl(\frac{1}{2}\left(2\lambda-\frac{2}{\lambda^{3}}\right)
\\
+\frac{519\left(2\lambda-\frac{2}{\lambda^{3}}\right)\left(\lambda^{2}+\frac{1}{\lambda^{2}}+1\right)^{4}}{134750N^{4}}
\\
+\frac{19\left(2\lambda-\frac{2}{\lambda^{3}}\right)\left(\lambda^{2}+\frac{1}{\lambda^{2}}+1\right)^{3}}{1750N^{3}}
\\
+\frac{11\left(2\lambda-\frac{2}{\lambda^{3}}\right)\left(\lambda^{2}+\frac{1}{\lambda^{2}}+1\right)^{2}}{350N^{2}}
\\
+\frac{\left(2\lambda-\frac{2}{\lambda^{3}}\right)\left(\lambda^{2}+\frac{1}{\lambda^{2}}+1\right)}{10N}\Biggr)
\end{multlined}

Which results in the pic attached.

I don´t like it a lot and I would like to know what could I do to have a better equation displaying there.

Thanks for your help.

[Johannes_B]

Not sure what you are looking for, maybe this:

Code: Select all

\documentclass{article}
\usepackage{mathtools}
\begin{document}
%    \begin{equation}
%    \begin{multlined}
\begin{align*}
    \frac{dW}{d\lambda} = \sigma_{1}-\sigma_{2}\nonumber
     =
     nk\Theta\times\Biggl(&\frac{1}{2}\left(2\lambda-\frac{2}{\lambda^{3}}\right)
    \\
    &+\frac{519\left(2\lambda-\frac{2}{\lambda^{3}}\right)\left(\lambda^{2}+\frac{1}{\lambda^{2}}+1\right)^{4}}{134750N^{4}}
    \\
    &+\frac{19\left(2\lambda-\frac{2}{\lambda^{3}}\right)\left(\lambda^{2}+\frac{1}{\lambda^{2}}+1\right)^{3}}{1750N^{3}}
    \\
    &+\frac{11\left(2\lambda-\frac{2}{\lambda^{3}}\right)\left(\lambda^{2}+\frac{1}{\lambda^{2}}+1\right)^{2}}{350N^{2}}
    \\
    &+\frac{\left(2\lambda-\frac{2}{\lambda^{3}}\right)\left(\lambda^{2}+\frac{1}{\lambda^{2}}+1\right)}{10N}\Biggr)
    \end{align*}
%    \end{multlined}
%    \end{equation}
\end{document}

[minidiable]

Like that it is nice but I can´t put anymore a label to the equation because it is just an :

\begin{align*}
...
\end{align*}

How can I put a label to this equation and how can I put a number of equation? If I remove the "*" I have numbers at every line.

Thanks for the help,
Fab.

[esdd]

Use an aligned environment inside equation :

Code: Select all

\documentclass{article}
\usepackage{mathtools}
\begin{document}
\begin{equation}\label{eq:longeq}
    \begin{aligned}[b]% the number will be at b(ottom)
    \frac{dW}{d\lambda} = \sigma_{1}-\sigma_{2}%\nonumber
     =
     nk\Theta\times\Biggl(&\frac{1}{2}\left(2\lambda-\frac{2}{\lambda^{3}}\right)
    \\
    &+\frac{519\left(2\lambda-\frac{2}{\lambda^{3}}\right)\left(\lambda^{2}+\frac{1}{\lambda^{2}}+1\right)^{4}}{134750N^{4}}
    \\
    &+\frac{19\left(2\lambda-\frac{2}{\lambda^{3}}\right)\left(\lambda^{2}+\frac{1}{\lambda^{2}}+1\right)^{3}}{1750N^{3}}
    \\
    &+\frac{11\left(2\lambda-\frac{2}{\lambda^{3}}\right)\left(\lambda^{2}+\frac{1}{\lambda^{2}}+1\right)^{2}}{350N^{2}}
    \\
    &+\frac{\left(2\lambda-\frac{2}{\lambda^{3}}\right)\left(\lambda^{2}+\frac{1}{\lambda^{2}}+1\right)}{10N}\Biggr)
    \end{aligned}
\end{equation}
See equation \eqref{eq:longeq}
\end{document}

equation.png (12.03 KiB) Viewed 18922 times

Best regards
Elke

[minidiable]

Thanks for the reply but to me it is not working.

Code: Select all

\begin{equation}\label{eq:stressStrain}
\begin{aligned}[b]
    \frac{dW}{d\lambda} = \sigma_{1}-\sigma_{2}\nonumber
     =
     nk\Theta\times\Biggl(&\frac{1}{2}\left(2\lambda-\frac{2}{\lambda^{3}}\right)
    \\
    &+\frac{519\left(2\lambda-\frac{2}{\lambda^{3}}\right)\left(\lambda^{2}+\frac{1}{\lambda^{2}}+1\right)^{4}}{134750N^{4}}
    \\
    &+\frac{19\left(2\lambda-\frac{2}{\lambda^{3}}\right)\left(\lambda^{2}+\frac{1}{\lambda^{2}}+1\right)^{3}}{1750N^{3}}
    \\
    &+\frac{11\left(2\lambda-\frac{2}{\lambda^{3}}\right)\left(\lambda^{2}+\frac{1}{\lambda^{2}}+1\right)^{2}}{350N^{2}}
    \\
    &+\frac{\left(2\lambda-\frac{2}{\lambda^{3}}\right)\left(\lambda^{2}+\frac{1}{\lambda^{2}}+1\right)}{10N}\Biggr)
    \end{aligned}
\end{equation}

What do I do wrong?

[esdd]

There is an active \nonumber in the first line of the aligned environment. Delete this command to get an equation number.

Best regards
Elke

[minidiable]

Thanks for your help.