若数列{an}中,a1=3,且a(n+1)=an^2(n是正整数),则数列的通项an=

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若数列{an}中,a1=3,且a(n+1)=an^2(n是正整数),则数列的通项an=
若数列{an}中,a1=3,且a(n+1)=an^2(n是正整数),则数列的通项an=

若数列{an}中,a1=3,且a(n+1)=an^2(n是正整数),则数列的通项an=
lga(n+1)=2lgan
所以lgan是等比数列,q=2
所以lgan=lga1*2^(n-1)=2^(n-1)*lg3=lg3^[2^(n-1)]
an=3^[2^(n-1)]

a5/b5
=(a5+a5)/(b5+b5)
=(a1+a9)/(b1+b9)
=[(a1+a9)×9÷2]/[(b1+b9)×9÷2]
=S9/S'9
=(5×9+3)/(2×9+7)
=48/25 a5/b5
=(a5+a5)/(b5+b5)
=(a1+a9)/(b1+b9)
=[(a1+a9)×9÷2]/[(b1+b9)×9÷2]
=S9/S'9
=(5×9+3)/(2×9+7)
=48/25