Question

3 + 12 + 48 + 192 +...

Tentukan!

a. Sn=
b. S8=

Answer 1

Sn = a (r^n-1)/ (r-1)
      = 3 (r^n-1)/(r-1)
rasionya = 12/3= 4
S8= a (r^n-1)/(r-1)
     = 3 (4^8-1)/ 4-1
     = 3 (65536-1)/3
S8= 65535
jadi 
Sn = 3 (r^n-1)/(r-1)
S8 = 65535
semoga bermanfaaat