Why this result?



(%i7) m : matrix([5,7], [5,x])$

(%i8) columnspace(m);
Proviso:  {x-7#0} 
(%o8) span(matrix([5],[5]),matrix([7],[x]))

>From (%o8), we see that provided x - 7 # 0, the rank of m is 2; similarly 
for the nullspace:

(%i9) nullspace(m);
Proviso:  {x-7#0} 
(%o9) span()

I prefer triangularize over echelon:

(%i10) triangularize(m);
(%o10) matrix([5,7],[0,5*x-35])

The proviso scheme isn't integrated into Maxima. Maybe it should be. Maybe 
it's a bad idea.
I don't know.

Barton

maxima-bounces at math.utexas.edu wrote on 08/22/2007 07:32:52 AM:

> Hi,
> 
> this is a small maxima session:
> 
> matrix(
>  [5,7], 
>  [5,x]
> );
> (%o3) matrix([5,7],[5,x])
> (%i4) echelon(%);
> (%o4) matrix([1,7/5],[0,1])
> 
> Why the result is [0,1] and not [0,x-7] ?
> 
> Thank you for your help!
> 
> Patrick
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