(1)∵Sn=
(an+1)2,∴a1=S1=1 4
(a1+1)2,∴a1=1(an>0)1 4
当n≥2时,an=Sn?Sn?1=
(an+1)2?1 4
(an?1+1)2,∴(an+an-1)(an-an-1-2)=01 4
∵an>0,
∴an-an-1=2,
∴{an}为等差数列.(4')
(2)由(1)知,{an}是以1为首项,2为公差的等差数列,
∴an=2n-1
∴bn=
,①2n?1 2n
Tn=
+1 2
+…+3 22
,①2n?1 2n
Tn= 1 2
+1 22
+3 23
+…+5 24
+2n?3 2n
②2n?1 2n
①-②得:
Tn=1 2
+2(1 2
+1 22
+1 23
+1 24
)?1 2n
2n?1 2n+1
∴Tn=3?
(2n?3 2n