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已知f(n)=+++…+,则( ) A.f(n)中共有n项,当n=2时,f(2)...
已知f(n)=
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+…+
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,则( )
A.f(n)中共有n项,当n=2时,f(2)=
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![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101230831659899512/SYS201311012308316598995004_ST/5.png)
B.f(n)中共有n+1项,当n=2时,f(2)=
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+
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101230831659899512/SYS201311012308316598995004_ST/8.png)
C.f(n)中共有n
2-n项,当n=2时,f(2)=
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D.f(n)中共有n
2-n+1项,当n=2时,f(2)=
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101230831659899512/SYS201311012308316598995004_ST/11.png)
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![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101230831659899512/SYS201311012308316598995004_ST/12.png)
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