基礎(chǔ)鞏固組
1.數(shù)列1,3,5,7,…,(2n-1)+,…的前n項和Sn的值等于( )
A.n2+1- B.2n2-n+1-
C.n2+1- D.n2-n+1-
2.(2014福建廈門模擬)已知函數(shù)f(x)=x2+bx的圖象在點A(1,f(1))處的切線的斜率為3,數(shù)列的前n項和為Sn,則S2 015的值為( )
A. B. C. D.
3.(2014山東濟南模擬)在數(shù)列{an}中,an+1+(-1)nan=2n-1,則數(shù)列{an}的前12項和等于( )
A.76 B.78 C.80 D.82
4.已知等比數(shù)列{an}中,a1=3,a4=81,若數(shù)列{bn}滿足bn=log3an,則數(shù)列的前n項和Sn= .
5.已知數(shù)列{an}的首項a1=3,通項an=2np+nq(nN*,p,q為常數(shù)),且a1,a4,a5成等差數(shù)列.求:
(1)p,q的值;
(2)數(shù)列{an}的前n項和Sn的公式.
6.(2014廣東惠州調(diào)研)已知向量p=(an,2n),向量q=(2n+1,-an+1),nN*,向量p與q垂直,且a1=1.
(1)求數(shù)列{an}的通項公式;
(2)若數(shù)列{bn}滿足bn=log2an+1,求數(shù)列{an·bn}的前n項和Sn.
7.在數(shù)列{an}中,a1=1,當(dāng)n≥2時,其前n項和Sn滿足=an.
(1)求Sn的表達式;
(2)設(shè)bn=,求數(shù)列{bn}的前n項和Tn.
8.(2014山東,文19)在等差數(shù)列{an}中,已知公差d=2,a2是a1與a4的等比中項.
(1)求數(shù)列{an}的通項公式;
(2)設(shè)bn=,記Tn=-b1+b2-b3+b4-…+(-1)nbn,求Tn.
能力提升組
9.已知等差數(shù)列{an}滿足a2=0,a6+a8=-10.
(1)求數(shù)列{an}的通項公式;
(2)求數(shù)列的前n項和.
10.設(shè)數(shù)列{an}滿足a1=2,an+1-an=3·22n-1.
(1)求數(shù)列{an}的通項公式;
(2)令bn=nan,求數(shù)列{bn}的前n項和Sn.
11.已知數(shù)列{an}的前n項和Sn=-n2+kn(其中kN*),且Sn的最大值為8.
(1)確定常數(shù)k,并求an;
(2)求數(shù)列的前n項和Tn.
12.已知正項數(shù)列{an},{bn}滿足a1=3,a2=6,{bn}是等差數(shù)列,且對任意正整數(shù)n,都有bn,,bn+1成等比數(shù)列.
(1)求數(shù)列{bn}的通項公式;
(2)設(shè)Sn=+…+,試比較2Sn與2-的大小.