另一设Ｃn=An/２的Ｎ次方，求Ｃn是等差数列
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数列Ａn的前Ｎ＋１项和＝４Ａn+2,A1=1,设Ｂn=Ａ(n+１）求数列Ｂn为等比数列Sn+1=4An+2Sn=4An+1Sn+1-Sn=4(An+2 -An+1)=An+1所以An+2=5A(n+1)/4 An=(5/4)^(n-1)Ｂn=Ａ(n+１)=(5/4)^n为等比数列设Ｃn=An/２^n，求Ｃn是等差数列Ｃn=(5/4)^(n-1)/２^nCn+1=(5/4)^n/２^(n+1)Cn+1/Cn =5/8Ｃn是等比数列
另一设Ｃn=An/２的Ｎ次方，求Ｃn是等差数列
数列Ａn的前Ｎ＋１项和＝４Ａn+2,A1=1,设Ｂn=Ａ(n+１）求数列Ｂn为等比数列Sn+1=4An+2Sn=4An+1Sn+1-Sn=4(An+2 -An+1)=An+1所以An+2=5A(n+1)/4 An=(5/4)^(n-1)Ｂn=Ａ(n+１)=(5/4)^n为等比数列设Ｃn=An/２^n，求Ｃn是等差数列Ｃn=(5/4)^(n-1)/２^nCn+1=(5/4)^n/２^(n+1)Cn+1/Cn =5/8Ｃn是等比数列