Equation Block alignment to the left

Question

i have three equations with number (reference) that i want to left align.

\documentclass[journal]{IEEEtran} 
\usepackage{cite} 
\usepackage{graphicx} 
\usepackage[labelfont=bf, figurename=Figure, font=small]{caption} \usepackage[subrefformat=parens, labelformat=parens, font=small]{subfig} \usepackage{url} 
\usepackage{textcomp} 
\usepackage{hyperref} 
\usepackage{microtype} 
\usepackage[dont-mess-around]{fnpct} 
\usepackage[misc]{ifsym} 
\usepackage[depth=subsubsection]{bookmark} 
\usepackage{booktabs} 
\usepackage{makecell} 
\usepackage{etoolbox} 
\usepackage{authblk} 
\usepackage{hhline} 
\usepackage{multirow} 
\usepackage{xparse} 
\usepackage{cleveref} 

\begin{document}
\begin{equation}\label{eq1}
x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}
\end{equation}

\begin{equation}\label{eq2}
\frac{d}{dx}r^n=nx^{n-1}
\end{equation}

\begin{equation}\label{eq3}
Length=\int_{a}^{b}\sqrt{[f't]^2+[g't]^2}dt
\end{equation}
\end{document}

By default, the equations are center aligned. How can i make them left aligned? I already tried \begin{flalign}...\end{flalign}, \begin{aligned}...\end{aligned} with [fleqn] it did not work for me. Any help will be highly appretiated.

Answer 1

Sorry, but your question is not very clear, so the following solutions are based on pure guessing:

\documentclass[journal]{IEEEtran}
\usepackage{nccmath}

\usepackage{lipsum} % for generating dummy text, not use in real document

\begin{document}
\lipsum[11]
\begin{align}
            x   & = \frac{-b\pm\sqrt{b^2-4ac}}{2a}          \label{eq1} \\
\frac{d}{dx}r^n & = nx^{n-1}                                \label{eq2} \\
\mathrm{Length} & = \int_{a}^{b}\sqrt{[f't]^2+[g't]^2}dt    \label{eq3}
\end{align}
or
\begin{fleqn}
\begin{equation}\label{eq1}
x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}
\end{equation}

\begin{equation}\label{eq2}
\frac{d}{dx}r^n=nx^{n-1}
\end{equation}

\begin{equation}\label{eq3}
Length=\int_{a}^{b}\sqrt{[f't]^2+[g't]^2}dt
\end{equation}
\end{fleqn}
\lipsum[11]

\end{document}

which gives :

or in case that all equations in your document should be left aligned:

\documentclass[journal]{IEEEtran}
\usepackage[fleqn]{amsmath}

\usepackage{lipsum} % for generating dummy text, not use in real document

\begin{document}
\lipsum[11]
 \begin{equation}\label{eq1}
x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}
\end{equation}

\begin{equation}\label{eq2}
\frac{d}{dx}r^n=nx^{n-1}
\end{equation}

\begin{equation}\label{eq3}
Length=\int_{a}^{b}\sqrt{[f't]^2+[g't]^2}dt
\end{equation}
or     
\begin{gather}
x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}            \label{eq1} \\
\frac{d}{dx}r^n=nx^{n-1}                    \label{eq2} \\
Length=\int_{a}^{b}\sqrt{[f't]^2+[g't]^2}dt \label{eq3}
\end{gather}
\lipsum[11]

\end{document}

which gives:

edit (1): If you will use a solution with fleqn environment, then you can set the indentation of equations by environment option (see [Bernard's][3] comment below). For example, for indentation of 2em:

\begin{fleqn}[2em]    
\begin{gather}
x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}            \label{eq1} \\
\frac{d}{dx}r^n=nx^{n-1}                    \label{eq2} \\
Length=\int_{a}^{b}\sqrt{[f't]^2+[g't]^2}dt \label{eq3}
\end{gather}
\end{fleqn}

will move left border of equations for 2em to right,

edit (2): As Barbara Beeton pointed in her comment below, the use of gather environments has advantages over use of separated equations. You can compare results in the second example (observe spacing between equations). If a page or column break is needed, amsmath provides \allowdisplaybreak command.

For more information about use of amsmath packages see (new) short math guide.

Answer 2

The flalign environment works, but you have to create at least a second column with an &:

\documentclass[journal]{IEEEtran}
\usepackage{cite}
\usepackage{graphicx}
\usepackage[labelfont=bf, figurename=Figure, font=small]{caption}
\usepackage[subrefformat=parens, labelformat=parens, font=small]{subfig}
\usepackage{url}
\usepackage{textcomp}
\usepackage{hyperref}
\usepackage{microtype}
\usepackage[dont-mess-around]{fnpct}
\usepackage[misc]{ifsym}
\usepackage[depth=subsubsection]{bookmark}
\usepackage{booktabs}
\usepackage{makecell}
\usepackage{etoolbox}
\usepackage{authblk}
\usepackage{hhline}
\usepackage{multirow}
\usepackage{xparse}
\usepackage{cleveref}
\usepackage{lipsum}
\usepackage{nccmath}
\usepackage{showframe}
\renewcommand{\ShowFrameLinethickness}{0.3pt}

\begin{document}

\lipsum[11]

  \begin{flalign}\label{eq1}
    & x =\frac{-b±\sqrt{b²-4ac}}{2a} & \\
    \label{eq2}
     & \frac{d}{dx}r^n =nx^{n-1} \\
     \label{eq6}
    & \text{Length} =∫_{a}^{b}√{[f't]²+[g't]²}\,dt
  \end{flalign}

Or even with the $ = $ signs aligned:

  \begin{flalign}\label{eqa1}
    x & =\frac{-b±\sqrt{b²-4ac}}{2a} & \\
    \label{eqa2}
    \frac{d}{dx}r^n & =nx^{n-1} \\
    \label{eqa6}
    \text{Length} & =∫_{a}^{b}√{[f't]²+[g't]²}\,dt
  \end{flalign}

\end{document}