Question

Tolong bantu pakai cranya ya

Answer 1

Verified answer

Dik: barisan geometri 9,27,81,243,...
Dit: Un=
Jwb:

Pada barisan geometri
Un = a(r^(n-1))
a = 9
U2/U1 = ar / a = 27/9
r = 3

maka Un = 9 . 3^(n-1) = 3^2 . 3^(n-1)
Un = 3 ^ (n-1+2) = 3^(n+1) (D)

Answer 2

A = 9
r = 27/9 = 81/27 = 243/81 = 3

Maka
Un = ar^n-1
Un = 9 x 3^(n-1)
Un = 3² x 3^(n-1)
Un = 3^n+1

Jawaban D