Mohon bantuannya....

Bab Barisan dan Deret
Matematika SMA Kelas XI

deret tak hingga
U2² = U1 x U3
(k - 2)² = (k + 6) (k - 6)
k² - 4k + 4 = k² - 36
4k = 4 + 36
k = 40 : 4
k = 10

U1 = k + 6 = 10 + 6 = 16
U2 = k - 2 = 10 - 2 = 8

r = U2 / U1 = 8/16 = 1/2

S~ = a / (1 - r)
S~ = 16 / (1 - 1/2)
S~ = 16 : 1/2
S~ = 32

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