suku ke-2 dan ke-5 suatu barisan geometri berturut turut adalah 3 dan 81. suku ke-9 barisan geometri tersebut adalah
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JAWABANN BY JINNAKAL
•U2 = -3
a.r = -3
•U5 = 81
a.r^4 = 81
a.r.r^3 = 81
-3.r^3 = 81
r^3 = 81:(-3)
r^3 = -27
r^3 = (-3)^3
r = -3
•a.r = -3
a.(-3) = -3
a = -3:(-3)
a = 1
•U9 = a.r^3x9
U9 = 1.(-3)^3x9
U9 = -27x9
U9 = -243
U2 = -3
a.r = -3
U5 = 81
a.r^4 = 81
a.r.r^3 = 81
-3.r^3 = 81
r^3 = 81:(-3)
r^3 = -27
r^3 = (-3)^3
r = -3
a.r = -3
a.(-3) = -3
a = -3:(-3)
a = 1
U4 = a.r^3
U4 = 1.(-3)^3
U4 = -27
