Displaying equation with a line break and all subsequent lines indented
The mathtools
provides the \MoveEqLeft
function which achieves exactly what you want. By default, it indents subsequent lines by 2em and it can be further customized with \MoveEqLeft[<number>]
which will indent subsequent line by <number>
ems:
\documentclass{article}
\usepackage{amsmath}
\usepackage{mathtools}
\begin{document}
\begin{align}
\MoveEqLeft |f_{n}(x)g_{n}(x) - f_{n}(x)g(x) + f_{n}(x)g(x) - f(x)g(x)| \\
&\leq |f_{n}(x)g_{n}(x) - f_{n}(x)g(x)| + |f_{n}(x)g(x) - f(x)g(x)| \\
&= |f_{n}(x)||g_{n}(x) - g(x)| + |g(x)||f_{n}(x) - f(x)| \\
&\leq M_{1}\epsilon + M_{2}\epsilon \\
&= \epsilon(M_1+M_2) \longrightarrow 0 \text{ as } n \to \infty
\end{align}
\begin{align}
\MoveEqLeft[4] |f_{n}(x)g_{n}(x) - f_{n}(x)g(x) + f_{n}(x)g(x) - f(x)g(x)| \\
&\leq |f_{n}(x)g_{n}(x) - f_{n}(x)g(x)| + |f_{n}(x)g(x) - f(x)g(x)| \\
&= |f_{n}(x)||g_{n}(x) - g(x)| + |g(x)||f_{n}(x) - f(x)| \\
&\leq M_{1}\epsilon + M_{2}\epsilon \\
&= \epsilon(M_1+M_2) \longrightarrow 0 \text{ as } n \to \infty
\end{align}
\end{document}
Is this what you want?
\begin{align*}
&|f_{n}(x)g_{n}(x) - f_{n}(x)g(x) + f_{n}(x)g(x) - f(x)g(x)| \\
&\qquad \leq |f_{n}(x)g_{n}(x) - f_{n}(x)g(x)| + |f_{n}(x)g(x) - f(x)g(x)| \\
&\qquad = |f_{n}(x)||g_{n}(x) - g(x)| + |g(x)||f_{n}(x) - f(x)| \\
&\qquad \leq M_{1}\epsilon + M_{2}\epsilon \\
&\qquad = \epsilon(M_1+M_2) \longrightarrow 0 \text{ as } n \to \infty
\end{align*}
If you use mathenv
of the mdwtools
collection,
you can use the enhanced {eqnarray}
environment.
It takes optional column specifiers:
r
,c
,l
for right-justified, centered, and left-justified math;L
for left-justified math that is considered to have width 2em;- and more (read the documentation) so you can completely emulate
the functionality of
amsmath
environments like{align}
and others.
Here, you'd use
\documentclass{article}
\usepackage{amstext}
\usepackage{mathenv}
\begin{document}
\begin{eqnarray*}[Ll]
|f_{n}(x)g_{n}(x) - f_{n}(x)g(x) + f_{n}(x)g(x) - f(x)g(x)| \\
&\leq |f_{n}(x)g_{n}(x) - f_{n}(x)g(x)| + |f_{n}(x)g(x) -
f(x)g(x)| \\
&= |f_{n}(x)||g_{n}(x) - g(x)| + |g(x)||f_{n}(x) - f(x)| \\
&\leq M_{1}\epsilon + M_{2}\epsilon \\
&= \epsilon(M_1+M_2) \longrightarrow 0 \text{ as } n \to \infty
\end{eqnarray*}
\end{document}