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From: Walter Roberson <roberson@hushmail.com>
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Subject: Re: equation solving
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Xref: news.mathworks.com comp.soft-sys.matlab:637605

Vaibhav wrote:
> I want to enter a equation of the form s^3+s^2+s^1+1
> But when I enter it gives an error message of unknown variable s.
> I need equation in this form only,since it is to be used further, for 
> dividing another equation.

s^3+s^2+s^1+1 is an expression, not an equation. An equation would have 
to have an '=' in it somewhere.

Symbolic expressions and functions and formula can only be represented 
in Matlab if you have the Symbolic Toolbox (which is part of the Student 
Edition.) If you do have the Symbolic Toolbox, see the documentation for 
sym()