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Topic: problem with finding equilibrium points of nonlinear system
Replies: 6   Last Post: Mar 13, 2013 9:01 AM

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Nasser Abbasi

Posts: 6,677
Registered: 2/7/05
Re: problem with finding equilibrium points of nonlinear system
Posted: Mar 8, 2013 3:06 PM
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On 3/8/2013 1:56 PM, gilraen wrote:
> Hi all,
> I need to find equilibrium points of nonlinear system which consist of 9 equations.
>It is complicated system, so when I tried find equilibrium points in this way:
> syms x1 x2
> solve(x*2+3,x2^3-2, x3-2*x2); (it is just example)
> it give warning:
> Warning: The solutions are parametrized by the symbols
> It means it cannot be solve analytically. I try to solve this problem numerically but I am stuck.
> Is there any method how can I find equillibrium points in matlab numerically?
> Any help will be appreciated.

You should post complete example, and not bits and pieces. The above could
not have worked as x is not defined, and x3 is not defined.

But it works for me:

syms x1 x2 x x3
sol=solve(x*2+3,x2^3-2, x3-2*x2);

EDU>> sol.x

EDU>> sol.x2

(3^(1/2)*16^(1/3)*i)/4 - 16^(1/3)/4
- (3^(1/2)*16^(1/3)*i)/4 - 16^(1/3)/4

EDU>> sol.x3
(3^(1/2)*16^(1/3)*i)/2 - 16^(1/3)/2
- (3^(1/2)*16^(1/3)*i)/2 - 16^(1/3)/2


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