Question

diketahui barisan geometri 1,6,36,......tentukan suku ke 6 dan jumlah 5 suku pertama barisan tersebut​

Answer 1

Jawaban:

U6 = 7.776

S5 = 1.555

Penjelasan dengan langkah-langkah:

U1 = a = 1

U2 = 6

U3 = 36

r = U2/U1 => 6/1 = 6

U6...?

Un = a×r^n-1

U6 = 1×6^6-1

U6 =1×6^5

U6 =1×7.776

U6 =7.776

S5...? (r=6 artinya r>1)

Sn = (a×(r^n)-1)) / (r-1)

S5 = (1×(6^5)-1)) / (6-1)

S5 = (1×(6^5)) / (5)

S5 = (1×(7.776)-1) / (5)

S5 = (7.775) / (5)

S5 = 1.555