Math & Science ⇒ left align just some equations

[ebjikki]

Hello there,

I wish to keep most of my equations (within equation, gathered, etc.) centered as by default. However, there are some pretty long formulas in my document which I need to spread over several lines.

Commands like \shoveleft{} and some others, within the appropriate environments, take care of the alignment, but not of the math indentation itself. I read about the possibility to set length of the math indentation under the package amsmath when loaded with option [fleqn]. (There seems to be much confusion about that anyway, if one reads various posts...) Doing that destroys, however, the look of the rest of my document.

Please, is there a possibility to get a zero math indentation on the left, but without fleqn? So that most of my equations will stay centered, but it will be visible with some pretty long ones? Thank you so much for helping.

[Stefan Kottwitz]

Hi,

welcome to the board!

You could use the flalign environment for this. Add & at the right of rows to push the equations to the left.

Stefan

[ebjikki]

Hello, thanks for welcome and for reply.

Unfortunately, that suggestion didn't seem to work with my document. What happens: In \documentclass[10pt]{article} and using the amsmath package, when I add flalign in between of a gather environment, it makes the equations aligned right, alongside the same column, which is fine - I just need to achieve this on the left. As said, I do not want to use the fleqn option, because about a half of all formulas I want to stay centered.

Secondly, I think that anyway I would want to adjust the blank space on the left. I have read about various posts on adjusting the mathindent, @mathmargin, etc., but neither of the typically proposed alternatives worked for me. Upon compilation, LaTeX reported 'undefined control sequence'.

So, my two questions are:
- How to get the alignment on the left?
- Please, can someone post the RIGHT combination of commands (including appropriate placement in the preamble or within document) to get zero math margins on the left (to be used under amsmath package, but without fleqn)?

I hope herewith my questions are more precise and very concrete. I need to finish quite a tough document, so your helping is very appreciated!

[ebjikki]

Hey there, I then solved the problem. I post here a small example.

Code: Select all

\documentclass[10pt]{article}
\usepackage{amsmath, nccmath}

\begin{document}
\noindent This is text.
\begin{fleqn}[0pt]
\begin{alignat}{2}
  & a = b + c \\
  & d = e + f
\end{alignat}
\end{fleqn}
\noindent This is text 2.
\begin{equation}
 g = h + i
\end{equation}
\end{document}

This way I can have selected (blocks of) equations left aligned to the same margin as the text. Hope it helps to some of you, too. If you also use minipage, check out some issues of the nccmath package with minipage. I don't need it for the moment.