Jawabanmu

2014-03-02T21:16:19+07:00
Sn= a(1-r^n)/1-r atau Sn= a(r^n-1)/r-1
2014-03-02T21:17:11+07:00
Sn = a(rn-1)/r-1 , jika r>1
      = a(1-rn)/1-r , jika r<1