已知数列{an}中,a1=2,sn是它的前n项和,并且s(n+1)=4an+2(n=1,2.).(1)设bn=a(n+1)—2an(n=1,2.),求证:数列{bn}是等比数列;(2)求数列{an}的通项公式及前n项和公式.
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![已知数列{an}中,a1=2,sn是它的前n项和,并且s(n+1)=4an+2(n=1,2.).(1)设bn=a(n+1)—2an(n=1,2.),求证:数列{bn}是等比数列;(2)求数列{an}的通项公式及前n项和公式.](/uploads/image/z/119982-30-2.jpg?t=%E5%B7%B2%E7%9F%A5%E6%95%B0%E5%88%97%7Ban%7D%E4%B8%AD%2Ca1%3D2%2Csn%E6%98%AF%E5%AE%83%E7%9A%84%E5%89%8Dn%E9%A1%B9%E5%92%8C%2C%E5%B9%B6%E4%B8%94s%28n%2B1%29%3D4an%2B2%28n%3D1%2C2.%29.%EF%BC%881%EF%BC%89%E8%AE%BEbn%3Da%28n%2B1%29%E2%80%942an%EF%BC%88n%3D1%2C2.%29%2C%E6%B1%82%E8%AF%81%EF%BC%9A%E6%95%B0%E5%88%97%7Bbn%7D%E6%98%AF%E7%AD%89%E6%AF%94%E6%95%B0%E5%88%97%EF%BC%9B%EF%BC%882%EF%BC%89%E6%B1%82%E6%95%B0%E5%88%97%7Ban%7D%E7%9A%84%E9%80%9A%E9%A1%B9%E5%85%AC%E5%BC%8F%E5%8F%8A%E5%89%8Dn%E9%A1%B9%E5%92%8C%E5%85%AC%E5%BC%8F.)
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