Consistent alignment of equations throughout entire paper

Question

I'm writing a thesis and want all equations to be left aligned but also commence from the exact same distance from the left margin. I desire a (perhaps) 1 inch gap between all my equations and the left margin.

At the moment, I do not know how to do this. The distance between the equation and the left margin is dependent on how long the equation is.

For example:

\documentclass[a4paper,11pt]{article}
\usepackage{amsmath}

\begin{document}

\begin{align}
&\bf{\hat{\delta}}_\emph{ij} = 123 \\
&i \in \{1,2,...,N\}; j \in \{\textrm{(2.1),(2.2),(2.3)}\}
\end{align}

\begin{align}
&\bf{\hat{\delta}}_\emph{ij} = 123 \\
&i \in \{1,2,...,N\}; j \in \{\textrm{(2.1),(2.2),(2.3),(2.3),(2.3),(2.3)}\}
\end{align}


\end{document} 

Answer 1

One way is to use the package option \usepackage[fleqn]{amsmath}:

Notes:

• The showframe package was used to show the page margins.
• You can control the amount of indent via \setlength{\mathindent}{<value>}.

Code:

\documentclass[a4paper,11pt]{article}
\usepackage{showframe}
\usepackage[fleqn]{amsmath}

\begin{document}

\begin{align}
&\bf{\hat{\delta}}_\emph{ij} = 123 \\
&i \in \{1,2,...,N\}; j \in \{\textrm{(2.1),(2.2),(2.3)}\}
\end{align}

\begin{align}
&\bf{\hat{\delta}}_\emph{ij} = 123 \\
&i \in \{1,2,...,N\}; j \in \{\textrm{(2.1),(2.2),(2.3),(2.3),(2.3),(2.3)}\}
\end{align}
\end{document}