12、设数列{an }的前n项和为Sn ,且 Sn=2a3 -4(1)设数列{an }的通项公式\x05(2)设Sn =logan ,求数列 (bn-b(n+1))分之一的前n项和
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12、设数列{an }的前n项和为Sn ,且 Sn=2a3 -4(1)设数列{an }的通项公式\x05(2)设Sn =logan ,求数列 (bn-b(n+1))分之一的前n项和
12、设数列{an }的前n项和为Sn ,且 Sn=2a3 -4
(1)设数列{an }的通项公式\x05
(2)设Sn =logan ,求数列 (bn-b(n+1))分之一的前n项和
12、设数列{an }的前n项和为Sn ,且 Sn=2a3 -4(1)设数列{an }的通项公式\x05(2)设Sn =logan ,求数列 (bn-b(n+1))分之一的前n项和
我觉得楼主题目有问题啊 Sn=2a3 -4?是这样吗?如果是的话,那么{an}中a1=-4,其他项为零
这是高一的波,,
(1)n=1,Sn=.....
n大于等于2,an=sn-s(n-1)=......
然后判断n=1时符不符合.
(2)带an进去算就行了
a1=-2 Sn-Sn-1=An
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