两等差数列﹛an﹜﹛bn﹜前n项和之比为5n+3/2n+7.则a5/b5的值为?(具体)

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两等差数列﹛an﹜﹛bn﹜前n项和之比为5n+3/2n+7.则a5/b5的值为?(具体)两等差数列﹛an﹜﹛bn﹜前n项和之比为5n+3/2n+7.则a5/b5的值为?(具体)两等差数列﹛an﹜﹛bn

两等差数列﹛an﹜﹛bn﹜前n项和之比为5n+3/2n+7.则a5/b5的值为?(具体)
两等差数列﹛an﹜﹛bn﹜前n项和之比为5n+3/2n+7.则a5/b5的值为?(具体)

两等差数列﹛an﹜﹛bn﹜前n项和之比为5n+3/2n+7.则a5/b5的值为?(具体)
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

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