2005 年全国高考数学试题数列集锦选择题1
(广东卷)已知数列nx满足122xx,1212nnnxxx,3,4,n⋯.若 lim2nnx,则 (B) (A) 32(B)3(C)4(D)52
(福建卷) 3.已知等差数列}{na中,12497,1,16aaaa则的值是( A )A. 15 B .30 C.31 D.64 3
(湖南卷)已知数列}{na满足)(133,0*11Nnaaaannn,则20a= (B )A.0 B .3C.3D.234
(湖南卷)已知数列{ log 2(an-1)} (n∈ N*)为等差数列,且a1=3,a2=5,则nnnaaaaaa12312lim111(= (C)A. 2B .23C.1D.215
(湖南卷)设f0(x)=sinx,f 1(x)=f0′(x),f2(x)=f1′(x),⋯ ,fn+ 1(x)= fn′(x), n∈N,则 f2005(x)=( C)A. sinxB .- sinxC.cosxD.- cosx6
(江苏卷) 在各项都为正数的等比数列{an}中,首项a1=3 ,前三项和为21,则 a3+ a4+ a5=(C ) ( A ) 33 ( B ) 72 ( C ) 84 ( D )189 7
(全国卷 II) 如果数列na是等差数列,则(B ) (A)1845aaaa(B) 1845aaaa(C) 1845aaaa(D) 1845a aa a8
(全国卷 II ) 11 如果128,,,a aa 为各项都大于零的等差数列,公差0d,则 (B) (A)1845a aa a(B) 1845a aa a(C) 1845aaaa(D) 1845a aa a9
(山东卷)na是首项1a =1,公差为 d =3 的等差数列,如果na =2005 ,则序号 n 等于 (C ) (A) 667 (B)668 (C)669