diketahui suku ke-2 dan ke-4 barisan geometri berturut-turut 16 dan 4. suku ke-10 barisan tersebut adalah

r⁴-² = 4/16 = ¼
r² = 2-²
r = 2-¹ = ½
U2 = ar
16 = a x ½
a = 16 x 2 = 32

U10 = ar^9 = 32 x ½^9 = 2^(5-9) = 2^-4
U10 = ½⁴ = 1/16

Mapel Matematika
Bab Baris dan Deret

Barisan Geometri
U2 = 16
ar = 16

U4 = 4
ar^3 = 4
ar.r^2 = 4
16r^2 = 4
r^2 = 1/4
r = 1/2

ar = 16
a = 16/r
a = 16/(1/2)
a = 32

U10
= ar^9
= 32(1/2)^9
= 32/512
= 1/16