Question

Qual o termo da PG (729, 2430, 8100...) é igual a 100.000 ?

preciso de cálculos

Answer 1

a1 = 729
a1q = 2430
q = 2430/729  = 10/3
an = 100.000
an = a1* q^n-1
100.000 = 729 * (10/3)^n-1
( 10/3)^n-1 = 100.000 / 729
(10/3)^(n-1)  = ( 10/3)^6
n-1 = 6
n = 6 + 1
n = 7 *****