Tentukan rumus suku ke - n dari barisan 1/2, 1/3, 2/9, 4/27

a = 1/2
r = (1/3) ÷ (1/2) = 1/3 × 2/1 = 2/3

Un = ar^(n-1)
Un = (1/2)(2/3)^(n-1)
= (1/2)(2/3)^n(2/3)^-1
= (1/2)(3/2)(2/3)ⁿ
= (3/4)(2/3)ⁿ
= 2^(n-2) / 3^(n-1)