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From: Torsten Hennig <Torsten.Hennig@umsicht.fhg.de>
Newsgroups: comp.soft-sys.matlab
Subject: Re: solve command
Date: Wed, 25 Mar 2009 05:01:39 EDT
Organization: The Math Forum
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Xref: news.mathworks.com comp.soft-sys.matlab:527502

> "Roger Stafford"
> <ellieandrogerxyzzy@mindspring.com.invalid> wrote in
> message <gqb5f0\$cuc\$1@fred.mathworks.com>...
>
> >   I am not sure what your problem is, Shane.
> Matrix multiplication obeys the associative law, so
> o A*(R*x) is equal to (A*R)*x.  Why not just do this:
> >
> >  x = (A*R)\b;
> >
> > It is a standard problem of n linear equations in n
> unknowns.  If A*R is non-singular it has a unique
> solution.
> >
> > Roger Stafford
>
> my problem is, that i cant build up the inverse
> matrix of R and therefor i need a solve command.

x = (A*R)\b  _is_ the command to solve the equation
A*(R*x) - b = 0 for x.

Of course, you could also solve in two steps for x:
y = A\b
x = R\y.

Best wishes
Torsten.
```