题目内容
当
时,
,![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232130078271040.png)
(I)求
;
(II)猜想
与
的关系,并用数学归纳法证明.
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823213007796546.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232130078111087.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232130078271040.png)
(I)求
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823213007858608.png)
(II)猜想
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823213007874388.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823213007905373.png)
(I)1/2 7/12 1/2 7/12
(II)![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823213007920851.png)
(II)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823213007920851.png)
本试题主要考查了数列的通项公式的求解和数学归纳法的运用。
解:(1)
,![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823213007952891.png)
,
(2)猜想:
即:
(n∈N*)
下面用数学归纳法证明
① n=1时,已证S1=T1
② 假设n=k时,Sk=Tk(k≥1,k∈N*),即:
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232130080611830.png)
则![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232130080761038.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232130081391623.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232130081701595.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823213008186419.png)
由①,②可知,对任意n∈N*,Sn=Tn都成立.
解:(1)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823213007936620.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823213007952891.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823213007967577.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823213007983824.png)
(2)猜想:
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823213007920851.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232130080301755.png)
下面用数学归纳法证明
① n=1时,已证S1=T1
② 假设n=k时,Sk=Tk(k≥1,k∈N*),即:
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232130080611830.png)
则
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232130080761038.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823213008092898.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232130081081464.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232130081391623.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232130081701595.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823213008186419.png)
由①,②可知,对任意n∈N*,Sn=Tn都成立.
![](http://thumb.zyjl.cn/images/loading.gif)
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