(1)设{an}的公差为d(d>0),{bn}的公比为q,
则
b2S2=q(6+d)=64
b3S3=q2(9+3d)=960
解得
或
d=2 q=8
(舍)
d=?
6 5 q=
40 3
所以an=3+2(n-1)=2n+1,n∈N*,
bn=8n-1,n∈N*.
(2)因为Sn=3+5+…+(2n+1)=n(n+2)
所以
+1 S1
+…+1 S2
=1 Sn
+1 1×3
+1 2×4
+…+1 3×5
=
1 n(n+2)