tentukan jumlah 6buah suku pertama dari masing-masing deret berikut! a.16+32+64+128+... b. 6+18+54+162+.. c. 256+64+16+4+...

a. 16 + 32 + 64 + 128 + ...
a = 16
r = 2

Sn = a(r^(n) - 1) ÷ (r - 1)
S6 = 16 × (2^(6) - 1) ÷ (2 - 1)
S6 = 16 × 63 ÷ 1
S6 = 1008

b. 6 + 18 + 54 + 162 + ...
a = 6
r = 3
Sn = a(r^(n) - 1) ÷ (r - 1)
S6 = 6 (3^(6) - 1) ÷ (3 - 1)
S6 = 6 × 728 ÷ 2
S6 = 2184

c. 256 + 64 + 16 + 4 + ...
a = 256
r = 1/2
Sn = a(1 - r^(n) ) ÷ (1 - r)
S6 = 256 (1 - (1/2)^6) ÷ (1 - 1/2)
S6 = [256 × 1 - 256 × 1/64] ÷ 1/2
S6 = (256 - 4) × 2
S6 = 252 × 2
S6 = 504