Question

can someone explain how you get the sum of the geometric sequence 8,-16,32... if there 15 terms

Answer 1

well common ratio r = -2
a=8
n=15
use this S = a(r^n -1)/(r-1)

Answer 2

so you get 87384?

Answer 3

am sorry am too lazy calculating,,but if you feed correct values in the formulla..you will surely get the correct ans ^_^

Answer 4

yess thank you!