Take the 2-minute tour ×
TeX - LaTeX Stack Exchange is a question and answer site for users of TeX, LaTeX, ConTeXt, and related typesetting systems. It's 100% free, no registration required.

In an align environment, how can I put a word such as "Now" or "And" at the left margin and still align equations on that line and subsequent lines with &?

share|improve this question

1 Answer 1

up vote 11 down vote accepted

You can use the flalign environment; another option (if the text must appear between two parts of the math expression) could be to use the \intertext command; in the following example I used \rlap inside flalign* to box the text using a zero width box, thus achieving a similar horizontal alignment to that of align*:

\documentclass{article}
\usepackage{amsmath}

\newcommand*\Text{% jut to generate filler text for the example
Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Ut purus elit,
vestibulum ut, placerat ac, adipiscing vitae, felis. Curabitur dictum gravida
mauris. Nam arcu libero, nonummy eget, consectetuer id, vulputate a, magna.
Donec vehicula augue eu neque. Pellentesque habitant morbi tristique senectus
et netus et malesuada fames ac turpis egestas. Mauris ut leo.}

\begin{document}

\Text
\begin{flalign*}
&& a &= b  & \\
\rlap{and} && &= c & \\
\rlap{and} && &= d. & \\
\end{flalign*}
\Text
\begin{align*}
a &= b  \\
 &= c 
\intertext{and} 
&= d.
\end{align*}

\end{document}

enter image description here

The vertical space introduced by the \intertext command from amsmath often seems excessive; the mathtools package offers \shortintertext to alleviate this situation.

share|improve this answer
2  
For visual appearance (horizontal alignment) similar to align*, I would use \text{\rlap{and}} in flalign*. –  Werner Jan 10 '12 at 2:29
    
@Werner: yes, good idea; thanks. –  Gonzalo Medina Jan 10 '12 at 7:14
3  
\rlap{and} is enough, no need for \text –  Herbert Jan 10 '12 at 7:30

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.