# Thread: Un+1 = (Un-1)^2, U1=k, U2+1=U1. find the possible values of k.

1. ## Un+1 = (Un-1)^2, U1=k, U2+1=U1. find the possible values of k.

To write it out a bit clearer:

Un+1 = (Un-1)2 , U1=k , U2 +1=U1

Find the possible values of k.

I really don't know how to approach this question. Help and advice appreciated.

Thanks

age

2. ## Re: Un+1 = (Un-1)^2, U1=k, U2+1=U1. find the possible values of k.

Originally Posted by agehayoshina
To write it out a bit clearer:

Un+1 = (Un-1)2 , U1=k , U2 +1=U1

Find the possible values of k.

I find this post hard to read.

Assuming that $U_{n+1}=(U_n-1)^2~\&~U_1=k$ and $U_2+1=U_1$ is correct, then

$(k-1)^2+1=k.$

3. ## Re: Un+1 = (Un-1)^2, U1=k, U2+1=U1. find the possible values of k.

Sorry, formatting isn't my forte. and thanks! this helped.