substitue n from (1)
n+1 = n+1
therefor true for n+1 for all n
take n=0 (as proven), then n=1 is also true, then n=2 is also true and so on and so forth
similarly the same can be proven for -1 using the same methods and thus applies from n=0, hence this is proven where n is any integer
EDIT: Volv gets full marks...
bah! c'mon, it's the same, except i did it backwards i knew i was missing something there . It's a nice trick though, you can solve pretty much every problem by doing it my way, and then writting everything "backwards" .
This post was edited on 05-20-2008 at 01:28 AM by Chrono.