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From: "David Doria" <daviddoria@gmail.com>
Newsgroups: comp.soft-sys.matlab
Subject: Re: log with syms variables?
Date: Fri, 22 Feb 2008 20:01:02 +0000 (UTC)
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Can someone at least confirm this is the way it works?

Thanks,

Dave

"David Doria" <daviddoria@gmail.com> wrote in message
<fpk2e6$4db$1@fred.mathworks.com>...
> if i do this
> 
> syms a b;
> simplify(log(a*b))
> 
> i get log(a*b)
> 
> if i do this:
> 
> syms a b positive;
> simplify(log(a*b))
> 
> i get log(a) + log(b)
> 
> The later is what I would like.  Is it necessary to declare
> the symbolic variables as 'positive'? Or am I doing
> something else wrong?
> 
> Thanks,
> 
> Dave