Question

Determine o número de termos da pg
(81,27,9...1/9)?

Answer 1

a1 = 81
a2 = 27
q = 27/81 = 1/3 ****
an = 1/9

an = a1 * q^n-1)
1/9 = 81 * (1/3)^n-1
( 1/3)^n-1 = 1/9 : 81/1 = 1/9 * 1/81 = 1/729 = (1/3)^6
n - 1 = 6
n = 6 + 1
n = 7 ****