题目内容
如果一个序列{
}满足
=2,
=
+2n(n为自然数),那么
是( )
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823033717980259.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823033717995243.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823033718011330.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823033718027277.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823033718042307.png)
A.9900 | B.9902 | C.9904 | D.10102 |
B
解:∵
=2,
+1=
+2n(n为自然数),
∴
=2+2×1,
=2+2×1+2×2=2+2×3,
…
=2+n(n-1),
∴
=2+100×(100-1)=9902.
故选B.
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823033717995243.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823033718027277.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823033718027277.png)
∴
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823033718245277.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823033718245286.png)
…
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823033718027277.png)
∴
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823033718276307.png)
故选B.
![](http://thumb.zyjl.cn/images/loading.gif)
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题目内容
A.9900 | B.9902 | C.9904 | D.10102 |