在数列{an}中,若an+1=an2an+1,a1=1,则a6=(  ) A.13 B.113 C.11 D.111

问题描述:

在数列{an}中,若an+1=

an
2an+1
,a1=1,则a6=(  )
A. 13
B.
1
13

C. 11
D.
1
11

∵an+1=

an
2an+1
,a1=1,
∴a2=
a1
2a1+1
=
1
3
,a3=
a2
2a2+1
=
1
5
,a4=
a3
2a3+1
=
1
7
,a5=
a4
2a4+1
=
1
9
,a6=
a5
2a5+1
=
1
11

故选D.