Find the number of terms and the sum of the geometric series below.
Answer:
Why the answer given is
but not
?
As far as I can remember(and I did series a long time ago), it does not matter how they are arranged. You should arrive at the same answer I think(EDIT: Yes you will).
If r < 1 then we use one of the arrangements, and if r > 1 then we use the other. (EDIT: Only to make things easier)