equations
\begin{equation}
\lefteqn{TPR=\frac{\sum_{i=1}^{N}\sum_{j=1}^{S}S_{SU_{ij}=1\mid PU=1 }}{\sumS_{PU=1}}*N}
\label{eqn:6}
\end{equation}
I am trying to write this equation. The denominator part is not coming proper and i am not able to left align the equation. I am in a two columned format. The problem is the equation is moving to the second column.
I would definitely go the second way with $\displaystyle: I find that it looks strange to have something centered after a bullet. To get the vertical alignment correct, just add [t] after \begin{aligned}, where "t" means "top". (See also the top of page 8 of the User's guide for the amsmath Package.)
Since you want a cheat sheet, I'd recommend the extract package. With a slightly different MWE:
\documentclass{article}
\usepackage[
active,
header=false,
copydocumentclass=true,
generate=\jobname-Cheatsheet,
extract-env={equation},
extract-cmdline={synopsis},
]{extract} % http://ctan.org/pkg/extract
\begin{extract*}
% Items executed in both the main and extracted document
% (extract manual, section 5.1)
\usepackage{amsmath}
\end{extract*}
\begin{extract}
% Items executed only in extracted document
\def\synopsis#1{#1}
\end{extract}
\def\synopsis#1{}
\begin{document}
First Euler observed that
\synopsis{Euler's equation tying together the five fundamental constants of mathematics}%
\begin{equation}
1 + e^{i \Pi} = 0.
\end{equation}
Then, Gauss discovered the normal distribution:
\synopsis{Normal distribution}%
\begin{equation}
P(x) = \frac{1}{{\sigma \sqrt {2\pi } }}e^{{{ - \left( {x - \mu } \right)^2 } \mathord{\left/ {\vphantom {{ - \left( {x - \mu } \right)^2 } {2\sigma ^2 }}} \right. \kern-\nulldelimiterspace} {2\sigma ^2 }}}
\end{equation}
Finally, Einstein proclaimed:
\synopsis{Equivalence of mass and energy}%
\begin{equation}
E = m C^2
\end{equation}
\end{document}
you get an original document of:
and an extracted document of:
\documentclass{article}
% Items executed in both the main and extracted document
% (extract manual, section 5.1)
\usepackage{amsmath}
% Items executed only in extracted document
\def\synopsis#1{#1}
\begin{document}
\synopsis{Euler's equation tying together the five fundamental constants of mathematics}%
\begin{equation}
1 + e^{i \Pi} = 0.
\end{equation}
\synopsis{Normal distribution}%
\begin{equation}
P(x) = \frac{1}{{\sigma \sqrt {2\pi } }}e^{{{ - \left( {x - \mu } \right)^2 } \mathord{\left/ {\vphantom {{ - \left( {x - \mu } \right)^2 } {2\sigma ^2 }}} \right. \kern-\nulldelimiterspace} {2\sigma ^2 }}}
\end{equation}
\synopsis{Equivalence of mass and energy}%
\begin{equation}
E = m C^2
\end{equation}
\end{document}
and:
This also works with your original \caption command.
Best Answer
To left align a moderately long equation, you can use the
alignenvironment, and the\MovEqLeft[number of ems](default is 1em), or, for the equation to begin at the left margin, theflalignenvironment. Needless to loadamsmathsincemathtoolsdoes it: