No13 tolong jawabplissssssss

½ + 1/6 + 1/12 + … + Un
a = ½
r = 1/6 ÷ ½ = 1/6 x 2 = 2/6 = ⅓

a) 3 pola berikutnya :
1/12 x ⅓ = 1/36
1/36 x ⅓ = 1/108
1/108 x ⅓ = 1/324

b) Un = a x rⁿ-¹
Un = ½ x ⅓ⁿ-¹
Un = ½ x 3¹-ⁿ

c) Sn = a x ( 1 – rⁿ)/(1-r)
Sn = ½ x ( 1 – ⅓ⁿ)/(1-⅓)
Sn = ½ ÷ ⅔ x (1 – ⅓ⁿ)
Sn = ¾(1 – ⅓ⁿ)