U3=16 u5=64 (pake barisan geometri) Carilah u9

U5=ar^4=64
U3=ar²=16
Dibagi jadi
r²=4
r=2
r=2 kepers
ar²=16
a(2)²=16
a=16/4
a=4
U9=ar^8
U9=4*(2)^8
U9=4*256
U9=1024

U3=16 ➡ ar^2=16
U5=64 ➡ ar^4=64
maka:
ar^4 / ar^2 = 64/16
r^2=4
[tex]r = \sqrt{4} \\ r = 2 \\ karena \: a {r}^{2} = 16 \\ a {(2)}^{2} = 16 \\ a(4) = 16 \\ a = 16 \div 4 \\ a = 4 [/tex]
[tex]sehingga \: u9 = a {r}^{9 - 1} = a {r}^{8} \\ = (4) {(2)}^{8} \\ = (4)(256) \\ u9=1024[/tex]
U9=1024