Question

What is the sum of the first five terms of the geometric series 2 − 8 + 32 −

S5 = −410
S5 = 410
S5 = 512
S5 = 682

Answer 1

∑ (n = 1 to 5) (2·(-4)^(n - 1))

S5 = 2·((-4)^5 - 1)/((-4) - 1) = 410