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