Question

PLEASE HELP MEE
What is the sum of a 6-term geometric sequence if the first term is 11, the last term is -11,264 and the common ratio is -4?

Answer 1

Sn = a(1 - r^n) / 1 - r

a = first term = 11
n = number of term = 6
r = common ratio = -4

Sn = (11)(1- -4^7) / (1 - -4) =?

Answer 2

use geometric series formula

Answer 3

a1=11 r= -4 n=6


S(9)= -9009
@dauspex ?