Question

Suatu barisan geometri diketahui U * 3 = 144 anU * 7 = 9 Tentukan U6 dari barisan tersebut.​

Answer 1

Penjelasan dengan langkah-langkah:

u3 = 144

u7 = 9

un = a x r^n - 1

u7/u3 = (a x r^7 - 1)/(a x r^3 - 1)

9/144 = r^6/r^2

1/16 = r^4

(1/2)^4 = r^4

r = 1/2

cari a

u3 = a x r^2

144 = a x (1/2)^2

144 = a x 1/4

a = 144 x 4

a = 576

• suku ke 6

un = a x r^n - 1

u6 = 576 x (1/2)^6 - 1

u6 = 576 x (1/2)^5

u6 = 576 x 1/32

u6 = 18