Question

What is `S_n` for a geometric series that has `a_1 = .11 , a_5 = 895.956875, r = 9.5`?

Answer 1

`S_5 ~~1001.35`

Explanation:

Assuming `n=5` for which sum to be found.

We know sum of geometric series up to `n` th term is

`S_n = a_1* (r^n-1)/(r-1)` Here `a_1=0.11 , r=9.5 , n=5`

`:. S_5 = a_1* (r^5-1)/(r-1)= 0.11 * (9.5^5-1)/(9.5-1) ~~1001.35` [Ans]