On Sat, May 14, 2011 at 11:23 AM, Aditya Mahajan <adityam@umich.edu> wrote:

On Sat, 14 May 2011, Alasdair McAndrew wrote:

Hello,

I'm trying to typeset some linear algebra exercises for my students; the
exercises will be within a table, and each second element will be a system
of linear equations. This sort of thing:

\starttable[|l|M|l|M|]
\NC (a) \NC %

\startmathalignment[n=7,align={right,middle,right,middle,right,middle,right}]
\NC 3x\NC +\NC 6y\NC -\NC 2z\NC =\NC -13\NR
\NC -6x\NC -\NC 9y\NC +\NC 5z\NC =\NC 22\NR
\NC 3x\NC +\NC 3y\NC -\NC 5z\NC =\NC -13\NR
\stopmathalignment
\NC (b) \NC %

\startmathalignment[n=7,align={right,middle,right,middle,right,middle,right}]
\NC x\NC +\NC 3y\NC +\NC 3z\NC =\NC -4\NR
\NC x\NC +\NC 4y\NC +\NC 5z\NC =\NC -5\NR
\NC 2x\NC +\NC 4y\NC +\NC 3z\NC =\NC -5\NR
\stopmathalignment
\NC\AR
\stoptable

But this doesn't work. There seems to be a problem with the mathalignment
environment within the table. What do I need enclose these in so that they
will be treated as displayed equations within the table environment?

(Untested): \framed[align=normal,width=fit]{\startformula \startmathalignment ... \stopmathalignment \stopformula}

math alignment is a display math environment, and must be inside a \startformula ... \stopformula.

Two comments:

1. You know about \definemathalignment, right?
2. I think that this effect can be obtained more easily using

\startitemize[two,columns,a]
\item ...
\item ..
\stopitemize

but you might need to insert a negative \vskip (or \blank) to get matrix to align with the item symbol.

Aditya
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