一、选择题
1.若数列{an}的通项公式是an=(-1)n(3n-2),则a1+a2+…+a10=( )
(A)15 (B) 12 (C)-12 (D)-15
2.(2012·厦门模拟)数列{an}的前n项和为Sn,若a1=1,an+1=3Sn(n≥1),则a6=( )
(A)3×44 ×44+1(B)3
(C)44 (D)44+1
3.(2012·长春模拟)在数列{an}中,a1=2,an+1=an+ln(1+ 则an=( )),
(A)2+lnn (B)2+(n-1)lnn
(C)2+nlnn (D)1+n+lnn