# Horizontal alignment of equation and text

I want to make a list of Quantum Mechanics formula like the format of the following picture. But I am confused about how to make the equations align to the left while the text to the right. Usually, if I use environment like, Align or Equation, the equation will be at the center.

I know I can use fleqn package, but it does not align the equations to the left enough as wee see from the picture I attached. My thought to approach this is to usefleqn, then put in the align environment, then use a bunch of \qquad to align for the text part, which is on the right side of the page. But I think this is silly.

Can anyone give me an example of this format? Or does anyone know if there are some cool packages for me to use so that my formula list would look as nice as this one?

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Or you can use the flalign* environment provided by the amsmath package:

\documentclass{article}
\usepackage{amsmath}
\usepackage[per-mode=symbol]{siunitx}
\usepackage[english]{babel}
\usepackage{blindtext}% dummy text
\begin{document}
\begin{flalign*}
&c=\frac1{\sqrt{\epsilon_0\mu_0}}=\SI{3e8}{\m\per\s} &&\text{speed of light}\\
&\epsilon_0=\SI{8.85e-12}{C^2\per \N\m^2} &&\text{permittivity in vacuum}\\
&\mu_0 =\SI{4\pi e-7}{\N\per\A^2} &&\text{permeability in vacuum}
\end{flalign*}
\blindtext
\end{document}


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Do you know how to make the equations more left? –  Lawerance Jul 29 '14 at 8:42
Do you really mean more left? The equations are already left aligned to the text body. –  esdd Jul 29 '14 at 9:09
I now know what I got confused about. Actually I want the text to look more left, instead of positioning more left on the text body. So, I should change the margin to make it look more left on the page. –  Lawerance Jul 29 '14 at 15:44

I would just use align inside the amsmath package. By putting the & on the LHS you can left-align your equations. For example, the first three rows of your table are:

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{align*}
&c=\frac1{\sqrt{\epsilon_0\mu_0}}=3\times 10^8 m/s &&\text{speed of light}\\
&\epsilon_0=8.85\times 10^{-12}C^2/Nm^2 &&\text{permittivity in vacuum}\\
&\mu_0 =4\pi\times 10^{-7}N/A^2 &&\text{permeability in vacuum}
\end{align*}

\end{document}


which gives:

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Really thank you! –  Lawerance Jul 29 '14 at 15:47

Since this is basically a table, I would use a tabular* with a \fill between the columns. That way, the table will be flush with the left and right margins of the text, which is what the OP seemed to desire.

\documentclass{article}
\usepackage{amsmath}
\def\boldcal#1{\ooalign{$\mathcal{#1}$\cr\kern.3pt$\mathcal{#1}$}}
\begin{document}
{\centering FINAL FORMULA LIST\\
\tabcolsep=0em
\renewcommand\arraystretch{2}
\begin{tabular*}{\textwidth}{l@{\extracolsep{\fill}}l}
$c = \dfrac{1}{\sqrt{\epsilon_0 \mu_0}} = 3 \times 10^8\,\text{m/s}$ &
speed of light \\
$\epsilon_0 = 8.85 \times 10^{-12}\,\text{C$^2$/Nm$^2$}$ &
permittivity in vacuum\\
$\mu_0 = 4\pi \times 10^{-7}\,\text{N/A$^2$}$ & permeabilty in vacuum\\
\textbf{Electrostatics} & \\
$\mathbf{E}(r) = \dfrac{1}{4\pi\epsilon_0} \displaystyle\int \dfrac{\rho(\mathbf{r}')}{\mathcal{R}^2}\dot{\boldcal{R}} d\tau'$ & Coulomb's Law\\
with the notation: & \\
\end{tabular*}
\par\medskip
}
\noindent This text just shows that the above table is left aligned and
right-aligned to the underlying text.
\end{document}


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Thanks a lot! I change the margin of the text to make it look more left. –  Lawerance Jul 29 '14 at 15:46