Question

O numero de termos da PG (400, 40... 4/1000) e:

Answer 1

Oi Louany

PG

u1 = 400
u2 = 40

razão
q = u2/u1 = 40/400 = 1/10

termo geral
un = u1*q^(n - 1)

4/1000 = 400*(1/10)^(n - 1)

(1/10)^(n - 1) = 4/400000 = 1/100000 

10^(1 - n) = 10^-5 

1 - n = -5 
n - 1 = 5

n = 6 termos