dik u1 = 2 u4 = 1/4 dit s5 = ....? mohon bantuan nya kak

U1 = a = 2
U4 = 1/4 => ar^3 = 1/4 => 2 r^3 = 1/4 => r^3 = 1/8 => r = 1/2
S5 = a(1 - r^5)/(1 - r)
= 2(1 - (1/2)^5)/(1 - 1/2)
= 2(1 - 1/32) / (1/2)
= 4 (31/32)
= 31/8
= 3 7/8
= 3,875