4

I have a long equation. I want to split and align left for that equation such that same "=" location. I used below code in latex. But it fails to display. Thanks 

\documentclass[preprint,12pt, sort&compress]{elsarticle}

\usepackage{mathtools}
\DeclarePairedDelimiter{\norm}{\lVert}{\rVert}
\DeclareMathOperator{\tr}{tr}

\usepackage{lipsum} % for dummy text

\begin{document}

\lipsum[1]
 \begin{equation*}\label{proof_lemma:3} 
            \begin{aligned}
            \frac{\partial E(\mu,\sigma,\theta,\beta)}{\partial \beta}=\int_\Omega \sum_{i=1}^N \frac{\partial r_i(x)}{\partial \beta}dx \\
            =-\int_\Omega \sum_{i=1}^N \left( \frac{( \mu-\sigma- \theta)}{\sigma_i}\right)dx\\
    -\int_\Omega \sum_{i=1}^N \left( \frac{( \mu-\sigma- \theta)}{\sigma_i}\right)dx-\int_\Omega \sum_{i=1}^N \left( \frac{( \mu-\sigma- \theta)}{\sigma_i}\right)dx-\int_\Omega \sum_{i=1}^N \left( \frac{( \mu-\sigma- \theta)}{\sigma_i}\right)dx
            \end{aligned}
             \end{equation*}
\end{document}

enter image description here

Jame
  • 689

2 Answers2

8

Use the ={}& trick:

\documentclass{article}
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage[mathscr]{euscript}
\usepackage{mathtools}
\usepackage{graphicx}
\usepackage{caption}
\usepackage{chngcntr}
\usepackage{apptools}
\usepackage{amsthm}
\usepackage{hyperref}

\newcommand{\diff}{\mathop{}\!d}

\begin{document}

\begin{equation*}
\begin{aligned}
\frac{\partial E(\mu,\sigma,\theta,\beta)}{\partial \beta}
={}& \int\limits_\Omega \sum_{i=1}^N \frac{\partial r_i(x)}{\partial \beta}\diff x \\
={}& -\int\limits_\Omega \sum_{i=1}^N \left( \frac{( \mu-\sigma- \theta)}{\sigma_i}\right)\diff x
     -\int\limits_\Omega \sum_{i=1}^N \left( \frac{( \mu-\sigma- \theta)}{\sigma_i}\right)\diff x\\
   & -\int\limits_\Omega \sum_{i=1}^N \left( \frac{( \mu-\sigma- \theta)}{\sigma_i}\right)\diff x
     -\int\limits_\Omega \sum_{i=1}^N \left( \frac{( \mu-\sigma- \theta)}{\sigma_i}\right)\diff x
\end{aligned}
\end{equation*}

\end{document}

Note how I defined a macro for the differential symbol and used \int\limits in order to push the Omega below the integral symbol, which is customary in this case.

Note that hyperref should be loaded last among the packages you have.

enter image description here

egreg
  • 1,121,712
  • I am very thankful to you. It is very nice answer. – Jame Nov 06 '15 at 13:31
  • I just asked you a small question that is when I use \frac to show the division such as one of term above. The integration symbol appears very small. Let see that $\frac{\int\limits_\Omega \sum_{i=1}^N \left( \frac{( \mu-\sigma- \theta)}{\sigma_i}\right)\diff x}{\int\limits_\Omega \sum_{i=1}^N \left( \frac{( \mu-\sigma- \theta)}{\sigma_i}\right)\diff x}$ – Jame Nov 06 '15 at 13:59
  • And I found that your solution may be error if \left( in first line, and \right) in second line, is it correct. I just got ! Extra }, or forgotten \right. – Jame Nov 06 '15 at 14:20
  • @user8430 For scaling integral sign see http://tex.stackexchange.com/questions/39181/big-integral-sign – Onner Irotsab Nov 06 '15 at 15:36
1

You can use the aligned environment like it follows:

\documentclass{article}

\usepackage{amsmath}


\begin{document}

\begin{equation*}
    \label{proof_lemma:3} 
    \begin{aligned}
        \frac{\partial E(\mu,\sigma,\theta,\beta)}{\partial \beta}&=\int_\Omega \sum_{i=1}^N \frac{\partial r_i(x)}{\partial \beta}dx \\[\jot]
        &=-\int_\Omega \sum_{i=1}^N \left( \frac{( \mu-\sigma- \theta)}{\sigma_i}\right)dx -\int_\Omega \sum_{i=1}^N \left( \frac{( \mu-\sigma- \theta)}{\sigma_i}\right)dx\\[\jot]
        &\quad -\int_\Omega \sum_{i=1}^N \left( \frac{( \mu-\sigma- \theta)}{\sigma_i}\right)dx
        -\int_\Omega \sum_{i=1}^N \left( \frac{( \mu-\sigma- \theta)}{\sigma_i}\right)dx 
    \end{aligned}
\end{equation*}

\end{document}

Note &= and &\quad.

I have added \\[\jot] to leave more space between the lines, but this is matter of choice.

enter image description here

Onner Irotsab
  • 433