Question

Tentukan banyaknya suku pada deret geometri berikut
a)3+6+12+...+Un=1533
b)1+3+9+...+Un=364

Answer 1

Verified answer

Deret Geometri

a][
3 + 6 + 12 + ... + Un = 1533
a = 3
r = u2/u1 = 6/3 = 2

Sn = a(r^n - 1)/(r - 1)
3(2^n - 1)/(2 - 1) = 1533
2^n - 1 = 1533/3
2^n = 511 + 1
2^n = 512
n = 9

b][
1 + 3 + 9 + ... + Un = 364
a = 1
r = 3/1 = 3

Sn = 364
1(3^n - 1)/(3 - 1) = 364
3^n - 1 = 364 × 2
3^n = 728 + 1
3^n = 3^6
n = 6

n = banyak suku