Geometri 5,10,20,…… U9= S5= Rumus= Un=a-r pangkat n-1 Sn=a(r pangkat n -1)/r-1 R=rasio

A = 5
r = 10/5 = 2

U9 = 5 x 2^8 = 5 x 256 = 1.280
S5 = 5 x (2^5 – 1)/(2-1) = 5 x (32 – 1) = 5 x 31 = 155

Diketahui :
a = 5
r = 2
ditanyakan :
U9 = ?

jawab :
U9 = ar^(9-1)
U9 = 5 X 2^8
U9 = 5 X 256
U9 = 1280

S5 = a (r^n – 1 ) / r – 1
S5 = 5 (2^5 – 1 ) / 1
S5 = 5 (31)
S5 = 155

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