2个等差数列{An}、{Bn}的前n项和之比为5n+3/2n-1.则A10/B10=多少?

问题描述:

2个等差数列{An}、{Bn}的前n项和之比为5n+3/2n-1.则A10/B10=多少?
详细解答

设5n+3/2n-1=t
则前10项和比为53/19
前9项和比为48/17
A10/B10=(53t-48t)/(19t-17t)=5/2