若两个等差数列{An},{Bn}的前n项和分别为An,Bn,且满足An/Bn=3n-1/(2n+3),则a13/b13=?
人气:206 ℃ 时间:2020-05-15 22:18:41
解答
a13/b13
=A(2*13-1)/B(2*13-1)
=A25/B25
=(3x5-1)/(2x25+3)
=74/53
备注:已知an,bn为等差数列,且前n项和为An,Bn,那么am/bm=A(2m-1)/B(2m-1).
公式不明白请追问哈
推荐
- 等差数列{An},{Bn}的前n项和为Sn与Tn,若Sn/Tn=2n/3n+1,则An/Bn的值是?
- 等差数列{an},{bn}的前n项和分别为Sn,Tn,若SnTn=2n3n+1,则anbn=( ) A.23 B.2n−13n−1 C.2n+13n+1 D.2n−13n+4
- 等差数列{an}、{bn}的前n项和分别为Sn、Tn,若Sn/Tn=2n/3n+1,求an/bn
- 等差数列{an},{bn}的前n项和分别为Sn,Tn,若Sn/Tn=2n/3n+1 ,则an/bn=
- 等差数列{an},{bn}的前n项分别为Sn,Tn,若Sn/Tn=2n/3n+1,则an/bn=多少?
- ___is the time of year when there are a lot of weddings in the U.S
- 关于碳酸与硅酸……
- You are the way of the gods? 什么意思
猜你喜欢