總復(fù)習(xí)數(shù)列練習(xí)一（文科）

1、（總復(fù)習(xí)）數(shù)列練習(xí)一1.(2014課標(biāo),16,5分)數(shù)列an滿足an+1=11-an,a8=2,則a1=.2.(2014湖南,16,12分)已知數(shù)列an的前n項(xiàng)和Sn=n2+n2,nN*.(1)求數(shù)列an的通項(xiàng)公式;(2)設(shè)bn=2an+(-1)nan,求數(shù)列bn的前2n項(xiàng)和.3.(2014大綱全國(guó),17,10分)數(shù)列an滿足a1=1,a2=2,an+2=2an+1-an+2.(1)設(shè)bn=an+1-an,證明bn是等差數(shù)列;(2)求an的通項(xiàng)公式.4.(2014天津,5,5分)設(shè)an是首項(xiàng)為a1,公差為-1的等差數(shù)列,Sn為其前n項(xiàng)和.若S1,S2,S4成等比數(shù)列,則a1=()A.2 B.-

2、2 C.12 D.-125.(2014課標(biāo),5,5分)等差數(shù)列an的公差為2,若a2,a4,a8成等比數(shù)列,則an的前n項(xiàng)和Sn=()A.n(n+1)B.n(n-1)C.n(n+1)2D.n(n-1)26.(2014江西,13,5分)在等差數(shù)列an中,a1=7,公差為d,前n項(xiàng)和為Sn,當(dāng)且僅當(dāng)n=8時(shí)Sn取得最大值,則d的取值范圍為.7.(2014重慶,16,13分)已知an是首項(xiàng)為1,公差為2的等差數(shù)列,Sn表示an的前n項(xiàng)和.(1)求an及Sn;(2)設(shè)bn是首項(xiàng)為2的等比數(shù)列,公比q滿足q2-(a4+1)q+S4=0.求bn的通項(xiàng)公式及其前n項(xiàng)和Tn.8.(2014廣東,13,5分)等

3、比數(shù)列an的各項(xiàng)均為正數(shù),且a1a5=4,則log2a1+log2a2+log2a3+log2a4+log2a5=.9.(2014大綱全國(guó),8,5分)設(shè)等比數(shù)列an的前n項(xiàng)和為Sn.若S2=3,S4=15,則S6=()A.31B.32C.63D.6410.(2014課標(biāo),17,12分)已知an是遞增的等差數(shù)列,a2,a4是方程x2-5x+6=0的根.(1)求an的通項(xiàng)公式;(2)求數(shù)列an2n的前n項(xiàng)和.11.(2014安徽,18,12分)數(shù)列an滿足a1=1,nan+1=(n+1)an+n(n+1),nN*.(1)證明:數(shù)列ann是等差數(shù)列;(2)設(shè)bn=3nan,求數(shù)列bn的前n項(xiàng)和Sn.12.(2014湖北,19,12分)已知等差數(shù)列an滿足:a1=2,且a1,a2,a5成等比數(shù)列.(1)求數(shù)列an的通項(xiàng)公式;(2)記Sn為數(shù)