两等差数列{an}和{bn},前n项和分别为Sn,Tn且Sn/Tn=7n+2/n+3则a2+a20/b7+b15=

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两等差数列{an}和{bn},前n项和分别为Sn,Tn且Sn/Tn=7n+2/n+3则a2+a20/b7+b15=

两等差数列{an}和{bn},前n项和分别为Sn,Tn且Sn/Tn=7n+2/n+3则a2+a20/b7+b15=
两等差数列{an}和{bn},前n项和分别为Sn,Tn且Sn/Tn=7n+2/n+3
则a2+a20/b7+b15=

两等差数列{an}和{bn},前n项和分别为Sn,Tn且Sn/Tn=7n+2/n+3则a2+a20/b7+b15=
a2+a20/b7+b15=a1+a21/b1+b21
Sn=n(a1+an)/2 Tn=n(b1+bn)/2
Sn/Tn=7n+2/n+3
当n=21时,S21/T21=[21(a1+a21)/2]/[21(b1+b21)/2]=(7*21+2)/(21+3)
化简得:a1+a21/b1+b21=149/24

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