Math & Science ⇒ Aligning Formulas To a Particular Operator

[fx101]

I'm sure this is a silly question, but I have searched tons of forum posts and looked through the AMSMATH manual and haven't found a solution...

Anyhow, I have a formula like this:

Part1 &=Part2=Part3 (line1)
(double arrow) part4=part5 (line2)
=Part6 (line3)

I want the double arrow aligned with the = between part1 and part2, and the = before part 6 to be aligned with the = between part 4 and part 5. However, I want each line to remain intact. That is, I don't want the equations split apart into columns. How do I go about doing this?

My original thinking was:

Code: Select all

\begin{align}
part1 &= part2 = part3 \\
&\Leftrightarrow part4 &= part5 \\
& &= part 6
\end{align}

However... the last line is a pain to get aligned to the second equal sign? How do I do this?

[frabjous]

There are a number of ways to do this. Perhaps Voss's mathmode document would provide some clues. Here's one suggestion using the alignat environment:

Code: Select all

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{alignat}{2}
part1 &= part2 &&= part3 \\
&\Leftrightarrow part4 &&= part5 \\
& & &= part6
\end{alignat}
\end{document}

alignat.png (1.91 KiB) Viewed 1353 times