breqn package is not working

Question

I am using the breqn package, but it is not working.

\begin{dmath}

\sqrt {-{\frac {-4\,c-k_{{2}}{x}^{2}+{x}^{2}\sqrt {4\,c+{k_{{2}}}^{2}}}{c}}}\sqrt {{\frac {4\,c+k_{{2}}{x}^{2}+{x}^{2}\sqrt {4\,c+{k_{{2}}}^{2}}}{c}}}{\it EllipticF} \left( 1/2\,x\sqrt {{\frac {-k_{{2}}+ \sqrt {
4\,c+{k_{{2}}}^{2}}}{c}}},1/2\,\sqrt {-{\frac {4\,c+2\,{k_{{2}}}^{2}+2\,k_{{2}}\sqrt {4\,c+{k_{{2}}}^{2}}}{c}}} \right) {\frac {1}{\sqrt {{\frac {-k_{{2}}+\sqrt {4\,c+{k_{{2}}}^{2}}}{c}}}}}{\frac {1}{\sqrt {8\,c-2\,{x}^{4}+4\,k_{{2}}{x}^{2}}}}=t
\end{dmath}

Welcome to TeX.sx! Please add a minimal working example (MWE) that illustrates your problem. It is considered a lot better to put in some code that will compile, as it makes it a lot easier for us to copy it into our text editor and work with it, and see exactly what it is you are trying to do. — Andrew Uzzell, Nov 01 '12 at 10:25
Another tip: If you indent lines by 4 spaces, they'll be marked as a code sample. You can also highlight the code and click the "code" button (with "{}" on it). — Andrew Uzzell, Nov 01 '12 at 10:26

Mico · Answer 1 · 2017-05-28T19:22:35.073

7

Examining your math expression, I can't see how it might be typeset across just two lines; at a minimum, three lines are required to typeset it properly. The following MWE does so, using the multline environment provided by the amsmath package.

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{multline*}
\sqrt {-\frac {-4c-k_2x^2+x^2\sqrt {4c+k_2^2}}{c}}\,
  \sqrt {\frac {4c+k_2x^2+x^2\sqrt {4c+k_2^2}}{c}} \\
\times \textit{EllipticF} 
  \left( \frac{1}{2}x\sqrt {\frac {-k_2+ \sqrt {4c+k_2^2}}{c}},
  \frac{1}{2}\sqrt {-\frac {4c+2k_2^2+2k_2\sqrt {4c+k_2^2}}{c}} \,\right) \\
\times \frac {1}{\sqrt \frac{-k_2+\sqrt {4c+k_2^2}}{c}}\,
  \frac {1}{\sqrt {8c-2x^4+4k_2x^2}}=t
\end{multline*}
\end{document}

enter image description here

edited May 28 '17 at 19:22

answered Nov 01 '12 at 11:10

Mico

506,678

1

To get the equation number (as in the original formula), use multline. I've come to a very similar input, removing the useless braces and many \, commands, adding the same as you did. :) However, I'm not very convinced about \times; perhaps \cdot? – egreg Nov 01 '12 at 11:32
@egreg - \times may indeed be a bit too prominent, visually speaking. If so, \cdot would certainly be a plausible alternative. At any rate, it would seem to be a good idea to make explicit that the items across the three lines are being multiplied together, using any multiplication symbol that does the job. – Mico Nov 01 '12 at 11:52

score 5 · Answer 2 · edited May 28 '17 at 19:26

Taking @Mico's answer and removing the forced \\ breaks and going back to breqn you will see that breqn can break this although I couldn't see a way to get the indentation, so the manual breaking is giving more pleasing appearance here, but sometimes manual breaking isn't really an option and breqn is what you want...

enter image description here

\documentclass{article}
\usepackage{breqn}
\begin{document}\pagestyle{empty}
\begin{dmath*}
\sqrt {-\frac {-4c-k_2x^2+x^2\sqrt {4c+k_2^2}}{c}}
\sqrt {\frac {4c+k_2x^2+x^2\sqrt {4c+k_2^2}}{c}}
\times \textit{EllipticF} 
\left( \frac{1}{2}x\sqrt {\frac {-k_2+ \sqrt {4c+k_2^2}}{c}},
\frac{1}{2}\sqrt {-\frac {4c+2k_2^2+2k_2\sqrt {4c+k_2^2}}{c}} \,\right)
\times \frac {1}{\sqrt \frac{-k_2+\sqrt {4c+k_2^2}}{c}}
\frac {1}{\sqrt {8c-2x^4+4k_2x^2}}=t
\end{dmath*}
\end{document}

breqn package is not working

2 Answers2