tulislah 5 suku pertama barisan geometri : a.U1=3/4, r=2 b.U1=64, r=1/2 c.U1=3, r=-2 d. U1=-27, r=1/3

a) Un = ar^n-1
U1 = a = ¾
U2 = ar = ¾ • 2 = 3/2
U3 = ar² = ¾ • (2)² = ¾ • 4 = 3
U4 = ar³ = ¾ • (2)³ = ¾ • 8 = 6
U5 = ar⁴ = ¾ • (2)⁴ = ¾ • 16 = 12
5 suku barisan = { ¾ , 3/2 , 3 , 6 , 12 }

b) U1 = a = 64
U2 = ar = 64 • ½ = 32
U3 = ar² = 64 • ( ½ )² = 64 • ¼ = 16
U4 = ar³ = 64 • ( ½ )³ = 64 • ⅛ = 8
U5 = ar⁴ = 64 • ( ½ )⁴ = 64 • 1/16 = ¼
5 suku barisan = { 64,32,16,8,¼ }

c) U1 = a = 3
U2 = ar = 3 • ( - 2 ) = ( - 6 )
U3 = ar² = 3 • (-2)² = 3 • 4 = 12
U4 = ar³ = 3 • ( -2)³ = 3 • ( -8) = ( - 24 )
U5 = ar⁴ = 3 • ( -2)⁴ = 3 • 16 = 48
5 suku barisan = { 3,-6,12,-24,48 }

d) U1 = a = - 27
U2 = ar = (-27) • ⅓ = (-9)
U3 = ar² = (-27) • (⅓)² = - 27 • 1/9 = ( - 3 )
U4 = ar³ = ( -27) • ( ⅓)³ = - 27 • 1/27 = ( -1)
U5 = ar⁴ = ( -27) • ( ⅓)⁴ = - 27 • 1/81 = -⅓
5 suku barisan = { -27,-9,-3,-1,-⅓ }