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

 Messages: [ Previous | Next ]
 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

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
-3/2
-3/2
-3/2

EDU>> sol.x2

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

--Nasser

Date Subject Author
3/8/13 Nasser Abbasi
3/8/13 Nasser Abbasi
3/8/13 Nasser Abbasi
3/13/13 Christopher Creutzig