Question

Suku kedua dan kelima barisan geometri masng-masing 8 dan 64. Suku kedelapan dari barisan tersbut adalah....

Answer 1

U2=ar= 8
u5=ar^4 = 64

r^3 = ar^4/ar = 64/8 = 8
r = 2
ar = 8
a x 2 = 8
a = 4

u8 = ar^7 =  4 x 2^7 = 4x128 =512

Answer 2

U2=a.r=8
u5=a.r^4=a.r .r^3
8r^3=64
r^3=8
r=2-->a=4

u8=a.r^7=4.128=512