Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

Topic: Simple Difference Equation problem
Replies: 2   Last Post: Jul 17, 2014 9:37 PM

 Messages: [ Previous | Next ]
 Ken.Pledger@vuw.ac.nz Posts: 1,412 Registered: 12/3/04
Re: Simple Difference Equation problem
Posted: Jul 17, 2014 8:03 PM

gyansorova@gmail.com wrote:

> Consider a simple scalar non-linear difference equation
>
> x(n+1)=x(n)-mu.x(n)^2+ mu.u
>
> where u is a positive constant input (say unity or whatever) and mu is
> selected for stability.
>
> The equilibrium point is when x(n+1)=x(n) giving
>
> x*=sqrt(u) - take positive root only here and assume mu>0.
>
> Linearise and we get
>
> x(n+1)=a.x(n)+mu.u
>
> where a=1-2.mu.sqrt(u)

I'm no expert at this, but why is that 2 there? Could it be that

a = 1 - mu.sqrt(u) ?

Ken Pledger.

Date Subject Author
7/17/14 gyansorova@gmail.com
7/17/14 Ken.Pledger@vuw.ac.nz
7/17/14 gyansorova@gmail.com