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=
,a1=1,则a6=( )an 2an+1
A. 13
B.
1 13
C. 11
D.
1 11
答
∵an+1=
,a1=1,an 2an+1
∴a2=
=a1 2a1+1
,a3=1 3
=a2 2a2+1
,a4=1 5
=a3 2a3+1
,a5=1 7
=a4 2a4+1
,a6=1 9
=a5 2a5+1
,1 11
故选D.