Re: Align with comments

[Aditya Mahajan <adityam@umich.edu>]

Hi David,

On Wed, 3 May 2006, David Arnold wrote:

> I think a while back you provided an align example with comments, such as:
>
> 2x+3=5              Add -3 to both sides
> 2x+3-3=5-3     Simplify
> 2x=2                   Divide both sides by 2
>
> Etc.
>
> Could you provide another sample of this for us?


Assuming that you want to align at the = in the equations, you can use 
the following

\startformula \startalign[m=2,distance=4em]
   \NC 2x + 3     \NC = 5     \NC\NC \text{Add -3 to both sides}   \NR
   \NC 2x + 3 - 3 \NC = 5 - 3 \NC\NC \text{Simplify}               \NR
   \NC 2x         \NC = 2     \NC\NC \text{Divide both sides by 2} \NR
\stopalign \stopformula

If you use this kind of thing frequently, you can add some 
syntax sugar.

\definemathalignment
   [aligncomments]
   [m=2,distance=4em]

\def\Comment#1\NR{\NC\NC\text{#1}\NR}

\startformula \startaligncomments
   \NC 2x + 3     \NC = 5     \Comment Add -3 to both sides   \NR
   \NC 2x + 3 - 3 \NC = 5 - 3 \Comment Simplify               \NR
   \NC 2x         \NC = 2     \Comment Divide both sides by 2 \NR
\stopaligncomments \stopformula

If you simply want to left align the equations, you can use

\definemathalignment
   [aligncomments]
   [n=1,align={left},m=2,distance=4em]

\def\Comment#1\NR{\NC\text{#1}\NR}

\startformula \startaligncomments
   \NC 2x + 3     = 5     \Comment Add -3 to both sides   \NR
   \NC 2x + 3 - 3 = 5 - 3 \Comment Simplify               \NR
   \NC 2x         = 2     \Comment Divide both sides by 2 \NR
\stopaligncomments \stopformula


Aditya
-- 
Aditya Mahajan, EECS Systems, University of Michigan
http://www.eecs.umich.edu/~adityam || Ph: 7342624008