Math & Science ⇒ Equation with numbering on the right and text on the left

[schlenkwad]

I wish to write a \begin{equation}\end{equation} line where the equation number shows on the right margin, AND have text flushleft on the same line.

I have tried:
{Sample text}\parbox{length}{\begin{equation} eq text \end{equation}}

This is a hit and miss method, where the length of parbox has to be adjusted by trial and error. Does anyone know of a LaTeX canned solution?

[Stefan Kottwitz]

Welcome to the forum!

You could to use the fleqn option (flush left equation).

Code: Select all

\documentclass[fleqn]{article}
\usepackage{amsmath}
\setlength{\mathindent}{0pt}
\begin{document}
\section{Test}
\begin{equation}
  y = f(x)
\end{equation}
\end{document}

Stefan

[schlenkwad]

Thank you Stefan_K for the idea. That is not quite it.

I need text be be left justified on the same line, with the equation material in the center, and the equation number right justified.

See my example for equationTest.

Code: Select all

\documentclass[fleqn]{article}
\usepackage{amsmath}
\setlength{\mathindent}{0pt}
\begin{document}
\section{Test}

\begin{equation}
\text{left hand text}\qquad\qquad\qquad\qquad\qquad  y = f(x)
\end{equation}
\end{document}

[Johannes_B]

What kind of text is this? Personally, i cannot recall having seen this in a science book.

What happens, if the text is a bit longer? Or on the other hand, what happens if the equation gets longer?

[schlenkwad]

Johannes_B, it would be something like:

and f(x)=sin(x)+cos(x) (1.1)

or, it could be more verbose, like:

it follows that f(x)=sin(x)+cos(x) (1.1)

where the word "and" or the words "it follows that" would be left justified, and the equation numbers would be right justified. This would not be used for long phrases.

[Stefan Kottwitz]

Also I suggest to look into good math books to see if this style of writing is used anywhere. Can you tell me a book where you saw it? I would be interested to know it.

Here's a suggestion showing at least a way:

Code: Select all

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\section{Test}
\begin{flalign}
\text{It follows that } && y &= f(x) &
\end{flalign}
\end{document}

I just think this style is unusual and hard too integrate with the text flow without manual intervention.

Stefan

[Johannes_B]

\intertext and \shortintertext from amsmath are meant for that.

Code: Select all

\documentclass{article}
\usepackage{mathtools}
\usepackage{blindtext}
\begin{document}
\section{Test}
\blindtext
\begin{gather}
	E = mcc
	\shortintertext{it follows that }
	y = f(x)
\end{gather}
\blindtext
\begin{gather}
	E = mcc
	\intertext{it follows that }
	y = f(x)
\end{gather}
\end{document}

[schlenkwad]

Thank you very much. This is great!

For one, "Heat and Thermodynamics", 7th Ed. ISBN 0-07-114816-7.

[Johannes_B]

Yeah, intertexts are quite common. But they don't end up on the same time.

You see, a bit of context is always good.
Glad that everything worked out fine.