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We just started geometric series ("suite" in french) in math. Anyways, I figured out a formula for calculating the sum of N elements and I came up with:
T(n) = ab^n
S(min, max) = a(b^(max+1)-b^min)/(b-1)
min = first element to sum
max = last element to sum
S(2,3) = ab^2 + ab^3 for example
Confirm?
*edit* fixed a few math errors and put the right equation :rolleyes:
Would S(2, 4) = ab^2 + ab^3 + ab^4 or ab^2 + ab^4?
ab^2 + ab^3 + ab^4
With S(2, 4)
a(b^(4+1)-b^2)/(b-1) = (ab^5-ab^2)/(b-1) = ab^4-ab-ab^5+ab^2 = -ab^5+ab^4+ab^2-ab <> ab^2 + ab^3 + ab^4
So I'd assume it works with all min-max = 1. Maybe it can be tweaked?
Maybe that b^min should be b^(min-1) ... *thinks*
Well, I have math class tomorrow to check it over.
I can't find any situation where the equation doesn't work, it seems fine to me??