已知S
n是数列
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101222906681444150/SYS201311012229066814441017_ST/0.png)
的前n项和;
(1)分别计算S
2-S
1,S
4-S
2,S
8-S
4的值;
(2)证明:当n≥1时,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101222906681444150/SYS201311012229066814441017_ST/1.png)
,并指出等号成立条件;
(3)利用(2)的结论,找出一个适当的T∈N,使得S
r>2008.
考点分析:
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