but it wasn't growing at an increasing rate - it had a limiting sum (i.e. it doesn't keep growing forever). Meaning yes, each year it will grow nine tenths of what it did the yr before...hence you dont add the one.
you keep r=0.9
you want it to be less each year
otherwise |r|>1, which means you can't have a limiting sum.
i concur!
Reallly? Well i still used r as 0.9 coz it wouldnt work with 1.9.... but I was just thinking about that now. But still hoping r was 0.9=]