数列{an}满足a1=12,an+1=1-1an,则a2013等于(  ) A.12 B.-1 C.2 D.3

问题描述:

数列{an}满足a1=

1
2
,an+1=1-
1
an
,则a2013等于(  )
A.
1
2

B. -1
C. 2
D. 3

∵数列{an}满足a1

1
2
an+1=1−
1
an

∴a2=-1,a3=2,a4
1
2

∴数列{an}是以3为周期的周期数列,
∴a2013=a3×671=a3=2.
故选C.