已知两个等差数列{an},{bn}的前n项的和分别为Sn,Tn.若Sn/Tn=(2n)/(3n+1).求an/bn A2/3 B(2n-1)/(3n-1) C(2n+1)/(3n+1) D(2n-1)/(3n+4)

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已知两个等差数列{an},{bn}的前n项的和分别为Sn,Tn.若Sn/Tn=(2n)/(3n+1).求an/bn A2/3 B(2n-1)/(3n-1) C(2n+1)/(3n+1) D(2n-1)/(3n+4)
已知两个等差数列{an},{bn}的前n项的和分别为Sn,Tn.若Sn/Tn=(2n)/(3n+1).求an/bn
A2/3 B(2n-1)/(3n-1) C(2n+1)/(3n+1) D(2n-1)/(3n+4)

已知两个等差数列{an},{bn}的前n项的和分别为Sn,Tn.若Sn/Tn=(2n)/(3n+1).求an/bn A2/3 B(2n-1)/(3n-1) C(2n+1)/(3n+1) D(2n-1)/(3n+4)
Sn/Tn=2n/(3n+1)
(a1+a1+(n-1)*d1)/(b1+b1+(n-1)*d2)
=2n/(3n+1)
(2a1-d+n*d1)/(2b1-d2+n*d2)=2n/(3n+1)
->2a1=d1,d1=2,->a1=1
2b1-d2=-1,d2=3->b1=1,
an=(1+(n-1)*2)=2n-1,
bn=(1+(n-1)*3)=3n-2,
an/bn=(2n-1)/(3n-2),

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