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已知等差数列{an}满足a2=3,Sn-Sn-3=51(n>3),Sn=100,...
已知等差数列{an}满足a2=3,Sn-Sn-3=51(n>3),Sn=100,则n的值为( )
A.8
B.9
C.10
D.11
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n}满足:
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2,b
3,b
4;
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n}的通项公式;
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n=a
1a
2+a
2a
3+a
3a
4+…+a
na
n+1,求实数a为何值时4aS
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n恒成立.
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