已知数列an前n项和为Sn,且满足a1=4,Sn+Sn+1=5/3an+1

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已知数列an前n项和为Sn,且满足a1=4,Sn+Sn+1=5/3an+1已知数列an前n项和为Sn,且满足a1=4,Sn+Sn+1=5/3an+1已知数列an前n项和为Sn,且满足a1=4,Sn+S

已知数列an前n项和为Sn,且满足a1=4,Sn+Sn+1=5/3an+1
已知数列an前n项和为Sn,且满足a1=4,Sn+Sn+1=5/3an+1

已知数列an前n项和为Sn,且满足a1=4,Sn+Sn+1=5/3an+1
林永嘉,把分给我把,哈哈.
Sn+S(n+1)=(5/3)a(n+1)=(5/3)[S(n+1)-Sn]
4Sn=Sn+1
Sn+1/Sn=4
则,Sn成等比数列
S1=a1
Sn=4*4^(n-1)=4^n
你的班长大人啊聪明啊.哈哈.不要崇拜姐啊.
再给点分.

Sn+S(n+1)=(5/3)a(n+1)=(5/3)[S(n+1)-Sn]
2S(n+1)=7Sn
Sn=S1(2/7)^(n-1)=4(2/7)^(n-1)
an=sn-s(n-1)=4(2/7)^(n-1)-4(2/7)^(n-2)
=4(2/7)^(n-1)-14(2/7)^(n-1)
=-10(2/7)^(n-1)

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