How can I break a long equation?

Question

Upon compiling, one of my equations extends out of my column width in my final output. Options I tried--

1. breqn package asks for expl3.sty file which the compiler is unable to locate, (would have been the easiest way in the {dmath} environment
2. // in the equation,
3. {split}, {multiline} environment of amsmath but none of the 3 approaches seem to work.

Any tip from your Texperience(!)?

PS: I use latest version of TexnicCenter (+MikTeX 2.9) and the equation is in the {equation} environment right now.

Answer 1

none of the 3 approaches seem to work

That is a bad sentence. Do you get any errors?

Here is an example of the documentation of amsmath with split

\documentclass{article}
\usepackage{amsmath}
\begin{document}

\begin{equation}\label{e:barwq}
\begin{split}
 H_c&=\frac{1}{2n} \sum^n_{l=0}(-1)^{l}(n-{l})^{p-2}
     \sum_{l _1+\dots+ l _p=l}\prod^p_{i=1} \binom{n_i}{l _i}\\
    &\quad\cdot[(n-l )-(n_i-l _i)]^{n_i-l _i}\cdot
      \Bigl[(n-l )^2-\sum^p_{j=1}(n_i-l _i)^2\Bigr].
\end{split}
\end{equation}

\end{document}

Answer 2

This at least compiles and produces output. Removed the extra closing brace in \usepackage{breqn}} and the extra \ in \end{\equation}, and commented out the \begin{comment}, \end{comment} blocks. Plus I think you had some extra blank lines that I removed, and I think the quad was intended to be \quad. Hope this gets you going...

\documentclass{article}%
\usepackage{amsmath}%
\usepackage{amsfonts}%
\usepackage{amssymb}%
\usepackage{graphicx}
\usepackage{verbatim}
\usepackage{breqn}
%-------------------------------------------

\begin{document}
%this equation 1 is ok
    \begin{equation}
        g\left[Pr(happy_{im}=1)\right]=\alpha_{0i}+\alpha_{1}.\left|living\_shock_{im}\right|+\epsilon_{im}
        \label{Original}
    \end{equation}
%this equation 2 is ok
\begin{equation}
        g\left[Pr(happy_{im}=1)\right]=\alpha_{0i}+\alpha_{1}.\left|living\_shock_{im}\right|+\beta.{year}+\epsilon_{im}
        \label{yearlytrend}
    \end{equation}


%to split3
%have commented it out as no pdf output is produced otherwise
%\begin{comment}
\begin{equation}
\begin{split}
        g\left[Pr(happy_{im}=1)\right]=\alpha_{0i}+\alpha_{1}.
            \left|living\_shock_{im}\right|+\\
        \quad+\beta.{year}+\gamma.region.
            \left|living\_shock_{im}\right|+\delta{region}+\epsilon_{im}
        \label{region}
\end{split}
\end{equation} 
%\end{comment}

%again no output produced when {dmath} environment of breqn used; commented out
%\begin{comment}
%to split4
\begin{dmath}
g\left[Pr(happy_{im}=1)\right]=\alpha_{0i}+\alpha_{1}.\left|
    living\_shock_{im}\right|+\beta.{year}+//+\gamma.demo_{iy}.\left|
    living\_shock_{im}\right|+\delta_{iy}.demo_{iy}+\epsilon_{im}
    \label{demo}
\end{dmath}
%\end{comment}

%to split5
\begin{equation}
\begin{split}
        g\left[Pr(happy_{im}=1)\right]=\alpha_{0i}+\alpha_{1}.\left|living\_shock_{im}\right|+\beta.{year}+\gamma_{1}.demo_{iy}.\\
\left|living\_shock_{im}\right|+\gamma_{2}.urbanpop\%_{iy}.\left|living\_shock_{im}    \right|+\delta_{1}.demo_{iy}+\delta_{2}.urbanpop\%_{iy}+\delta_{3}.population+\epsilon_{im}
        \label{size}
\end{split}
\end{equation}

\end{document}