Diketahui 1/16 + 1/8 + 1/4+....+16=x.nilai x adalah

Kelas 8 Matematika
Bab Barisan dan Deret Bilangan

r = U2 : U1
r = (1/8) : (1/16)
r = (1/8) x 16
r = 2

Un = 16
a . rⁿ⁻¹ = 2⁴
(1/16) . 2ⁿ⁻¹ = 2⁴
2⁻⁴ . 2ⁿ⁻¹ = 2⁴
2ⁿ⁻⁵ = 2⁴
n - 5 = 4
n = 4 + 5
n = 9

Sn = a . (rⁿ - 1) / (r - 1)
S9 = (1/16) . (2⁹ - 1) / (2 - 1)
S9 = (1/16) . (512 - 1) / 1
S9 = 511/16
S9 = 31 15/16