Originally Posted by

**kl.twilleger** A problem from class where we're trying to figure out the spread of disease.

__Newly infected__ __Total Infected__

0 1

2 3

4 7

9 16

12 28

4 32

0 32

$\displaystyle I_{n+1} = I_{n} + G_{n}$

$\displaystyle G_{n} = aI_{n}(N+I_{n})$

$\displaystyle I_{n+1} = I_{n} + aI_{n}(N+I_{n})$

What happens to the difference equation when everyone is infected?

What happens when no one is infected?

For $\displaystyle G_{n}$, is it possible for $\displaystyle I_{n}$ to decrease?

I don't know where to start.... HELP!!