# Homework Help: Converegence Problem for forward and backward propogation

1. Sep 13, 2012

### aashish.v

The function is J(n-1)+J(n+1)=2nJ(n)

I need to prove that it diverges in forward direction but converges in backward direction.
I am unable to find any method, kindly suggest.

2. Sep 13, 2012

### camjohn

Are you sure that you typed the function correctly?

3. Sep 13, 2012

### aashish.v

Yes.

for forward direction we can re-write it this way..
J(n)=2*(n-1)*J(n-1)-J(n-2)

and for backward propogation...
J(n)=2*(n+1)*J(n+1)-J(n+2)

4. Sep 13, 2012

### aashish.v

5. Sep 13, 2012

### Ray Vickson

You need to show your work.

RGV

6. Sep 13, 2012

### aashish.v

The typical approach shown in text is to show that if the solution of such function truns out to be in form of
$C.λ^n$ then we can say that such recursive function diverges, I have tried the same approach for the problem but the λ I am getting turns out to be function of n.

I can scan and upload my work if you wish.