(1)证明:因为an=2an-1+1(n≥2),所以an+1=2(an-1+1)(n≥2),
所以数列{an+1}是以a1+1=2为首项,以2为公比的等比数列.
(2)解:由(1)知,an+1=2?2n-1=2n,∴an=2n-1
∴bn=log2(an+1)=n;
(3)解:
=1
bnbn+2
=1 n(n+2)
(1 2
-1 n
)1 n+2
∴Sn=
[(1-1 2
)+(1 3
-1 2
)+…+(1 4
-1 n
)]=1 n+2
(1+1 2
-1 2
-1 n+1
)=1 n+2
-3 4
-1 2(n+1)
.1 2(n+2)