已知数列{an}满足a1=1,an+1=2an+3.(Ⅰ)证明{an+3}是等比数列,并求{an}的通项公式;(Ⅱ)令bn=log2(an+3),求数列{1bn•bn+1}的前n项和Tn.
<p>问题:已知数列{an}满足a1=1,an+1=2an+3.(Ⅰ)证明{an+3}是等比数列,并求{an}的通项公式;(Ⅱ)令bn=log2(an+3),求数列{1bn•bn+1}的前n项和Tn.<p>答案:↓↓↓<p class="nav-title mt10" style="border-top:1px solid #ccc;padding-top: 10px;">黄承光的回答:<div class="content-b">网友采纳 (Ⅰ)证明:由题意得,an+1=2an+3,所以an+1+3an+3=2an+6an+3=2又a1=1,则a1+3=4,所以{an+3}是以4为首项、以2为公比的等比数列,则an+3=4•2n-1,即an=2n+1-3;(Ⅱ)由(Ⅰ)得,bn=log2(an+3)=n+1,所以1bn•b...
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