Question

O número de termos da PG (27, 9, ..., 1/9) é:

Answer 1

Razão = segundo termo / primeiro termo

q = 9 / 27

q = 1/3 ✓

an = a1 . q^n - 1

1/9 = 27 . (1/3)^n -1

1/9 / 27 = (1/3)^n-1

1/27 . 1/9 = (1/3)^n-1

1/243 = (1/3)^n-1

(1/3)^5 = (1/3)n-1

simplifica as bases

5 = n - 1

5 + 1 = n

6 = n

n = 6