diketahui barisan geometri dengan U6=114 dan U12=912..suku pertama dan rasio barisan tersebut adalah

jawab

u6 = 114
u12 = 912

u12/u6 = 912 /114
r⁶ = 8 = (2)³

r = (2)^(3/6) = (2)^(1/2)
r = √2

u6 = 114
a. r⁵ =114
a= 114/(r⁵) = 114/4√2
a= 114 (√2)/(8)
a = (114/8)√2
a = 57/2  √2

Kelas 9 Matematika
Bab Barisan dan Deret Bilangan

^ = pangkat

1] r = ^(12 - 6)√(U12/U6)
r = ^6√(912/114)
r = ^6√8
r = ^6√(2^3)
r = √2

2] a = U6 : r^5
a = 114 : (√2^5)
a = 114 / (2^(5/2))
a = 114 / (2² . 2^(1/2))
a = 114 / (4 √2)
a = 57/(2√2) . (√2)/(√2)
a = (57/4) √2