U9=128,U4=4,Hitunglah S20!
Matematika
Devy1213
Pertanyaan
U9=128,U4=4,Hitunglah S20!
1 Jawaban
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1. Jawaban khominghoo
u9 = 128
u4 = 4
r^9-4 = 128/4
r^5 = 32
r = 2
u4 = ar³ = 4
a x 2³ = 4
a = 4/8 = ½
s20 = ½ x (2^20 - 1)/(2-1)
= ½ x 1.048.575
= 524.287,5