Question

Numa PG infinita (1/3, -1/9, 1/27, ...) a soma dos termos é:
(A) 1/2
(B) 1
(C) 1/4
(D) 1/3

Answer 1

Resposta:

PG

u1 = 1/3

u2 = -1/9

q = u2/u1 = (-1/9)/(1/3) = -1/3

soma infinita

Sn = u1/(1 - q)

Sn = (1/3)/(1 + 1/3)

Sn = (1/3)/(4/3) = (1/3)*(3/4) = 1/4 (C)