设数列{an}是首项为a1(a1>0),公差为2的等差数列,前n项和为Sn,且根号S1,根号S2,根号S3成等差数列,(1)求数列{an}的通项公式.(2)记bn=an/(2^n)的前n项和为Tn,求Tn.
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![设数列{an}是首项为a1(a1>0),公差为2的等差数列,前n项和为Sn,且根号S1,根号S2,根号S3成等差数列,(1)求数列{an}的通项公式.(2)记bn=an/(2^n)的前n项和为Tn,求Tn.](/uploads/image/z/1741134-30-4.jpg?t=%E8%AE%BE%E6%95%B0%E5%88%97%7Ban%7D%E6%98%AF%E9%A6%96%E9%A1%B9%E4%B8%BAa1%28a1%3E0%29%2C%E5%85%AC%E5%B7%AE%E4%B8%BA2%E7%9A%84%E7%AD%89%E5%B7%AE%E6%95%B0%E5%88%97%2C%E5%89%8Dn%E9%A1%B9%E5%92%8C%E4%B8%BASn%2C%E4%B8%94%E6%A0%B9%E5%8F%B7S1%2C%E6%A0%B9%E5%8F%B7S2%2C%E6%A0%B9%E5%8F%B7S3%E6%88%90%E7%AD%89%E5%B7%AE%E6%95%B0%E5%88%97%2C%EF%BC%881%EF%BC%89%E6%B1%82%E6%95%B0%E5%88%97%EF%BD%9Ban%EF%BD%9D%E7%9A%84%E9%80%9A%E9%A1%B9%E5%85%AC%E5%BC%8F.%EF%BC%882%EF%BC%89%E8%AE%B0bn%3Dan%2F%282%5En%29%E7%9A%84%E5%89%8Dn%E9%A1%B9%E5%92%8C%E4%B8%BATn%2C%E6%B1%82Tn.)
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设数列{an}是首项为a1(a1>0),公差为2的等差数列,前n项和为Sn,且根号S1,根号S2,根号S3成等差数列,(1)求数列{an}的通项公式.(2)记bn=an/(2^n)的前n项和为Tn,求Tn.
设数列{an}是首项为a1(a1>0),公差为2的等差数列,前n项和为Sn,且根号S1,根号S2,根号S3成等差数列,
(1)求数列{an}的通项公式.
(2)记bn=an/(2^n)的前n项和为Tn,求Tn.
设数列{an}是首项为a1(a1>0),公差为2的等差数列,前n项和为Sn,且根号S1,根号S2,根号S3成等差数列,(1)求数列{an}的通项公式.(2)记bn=an/(2^n)的前n项和为Tn,求Tn.
设首项为a(值这样书写容易点),根号S1、根号S2、根号S3成等差,解出a=1,所以an=2n-1.
bn是一个等差和等比相乘的数列,用错位法求和.
题目有问题,此题无解
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