∵an+12=an2+2an+1=(an+1)2且an>0
∴an+1=an+1
∵a1=1
∴数列{an}是以1为首项,以1为公差的等差数列
∴an=1+n-1=n
∴
=1
an+1an
=1 n(n+1)
?1 n
1 n+1
∴
+1
a1a2
+…+1
a2a3
1
anan+1
=
+1 1×2
+…+1 2×3
1 n(n+1)
=1-
+1 2
?1 2
+…+1 3
?1 n
1 n+1
=1-
1 n+1
故选C