Question

Diketahui deret geometri Sk = 54+18+6+2+..........+uk. Tentukan nilai S7

Answer 1

A=54 dan r=1/3
S7 = a(1-r^6)/1-r
     = 54*(1- (1/3)^7)/(1- 1/3)
     = 27 * 3 (3^7 - 1)/3^7
     = 2186/27