设数列{a
n}的前n项的和
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102807464582789/SYS201311031028074645827018_ST/0.png)
,n∈N
*(1)求首项a
1与通项a
n;
(2)设
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102807464582789/SYS201311031028074645827018_ST/1.png)
,c
n=tanb
n•tanb
n+1,求数列{c
n}的前n项和T
n.
考点分析:
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(I) 求△ABC的周长;
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设
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![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102807464582789/SYS201311031028074645827016_ST/1.png)
时,求f(x)的值域;
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在数列{a
n}中,如果对任意的n∈N
*,都有
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102807464582789/SYS201311031028074645827015_ST/0.png)
(λ为常数),则称数列{a
n}为比等差数列,λ称为比公差.现给出以下命题,其中所有真命题的序号是
.
①若数列{F
n}满足F
1=1,F
2=1,F
n=F
n-1+F
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②若数列{a
n}满足
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102807464582789/SYS201311031028074645827015_ST/1.png)
,则数列{a
n}是比等差数列,且比公差λ=2;
③等差数列是常数列是成为比等差数列的充分必要条件;
(文)④数列{a
n}满足:
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102807464582789/SYS201311031028074645827015_ST/2.png)
,a
1=2,则此数列的通项为
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102807464582789/SYS201311031028074645827015_ST/3.png)
-1,且{a
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(理)④数列{a
n}满足:a
1=
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102807464582789/SYS201311031028074645827015_ST/4.png)
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n=
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102807464582789/SYS201311031028074645827015_ST/5.png)
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n=
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102807464582789/SYS201311031028074645827015_ST/6.png)
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