1.等差数列{an}前n项和为Sn,①S4≥10,S5≤15,求a4最大值;②a(2n)/an=(4n-1)/(2n-1),求S20/S10;2.设{an}前n项和为Sn,a1=1,S(n+1)=4an+2(1)设bn=a(n+1)-2an,证{bn}为等比数列(2)求an
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/12 01:18:00
![1.等差数列{an}前n项和为Sn,①S4≥10,S5≤15,求a4最大值;②a(2n)/an=(4n-1)/(2n-1),求S20/S10;2.设{an}前n项和为Sn,a1=1,S(n+1)=4an+2(1)设bn=a(n+1)-2an,证{bn}为等比数列(2)求an](/uploads/image/z/400169-65-9.jpg?t=1.%E7%AD%89%E5%B7%AE%E6%95%B0%E5%88%97%7Ban%7D%E5%89%8Dn%E9%A1%B9%E5%92%8C%E4%B8%BASn%2C%E2%91%A0S4%E2%89%A510%2CS5%E2%89%A415%2C%E6%B1%82a4%E6%9C%80%E5%A4%A7%E5%80%BC%EF%BC%9B%E2%91%A1a%282n%29%2Fan%3D%284n-1%29%2F%282n-1%29%2C%E6%B1%82S20%2FS10%EF%BC%9B2.%E8%AE%BE%7Ban%7D%E5%89%8Dn%E9%A1%B9%E5%92%8C%E4%B8%BASn%2Ca1%3D1%2CS%28n%2B1%29%3D4an%2B2%281%29%E8%AE%BEbn%3Da%28n%2B1%29-2an%2C%E8%AF%81%7Bbn%7D%E4%B8%BA%E7%AD%89%E6%AF%94%E6%95%B0%E5%88%97%EF%BC%882%EF%BC%89%E6%B1%82an)
xUNA~^nmwgv11+d'DoEvDL9#GPJwivfWl7EKQc-
|xCp̫KMpE[Llٙ,l8wА)N^PW{|g{Zg~-ʈJ[pZĶUD6p{x3EEeQe -1BeSfv&Kl4 dqT!ߵːX)zn
~/Akl/-^jYWd{)6|%E=sox 1{їeO~> S=HugM|I%?GKp:9d@6R, EW 7ꆫS ͐Ɋty>o
eB2K
>a
1)&ES)EqPHl,v:~uSY42Rr=]č<dž.28m|! )Ũ}
c-Oǒ63)<4#`X;_ÍXugbf1ydWo3P)!B1xzM
jcDCc;