(1)a1=2,an=Sn-Sn-1=2n-1(n≥2).
∴bn={1/n (n≥2)
{2/3 (n=1)
(2)∵cn=T2n+1-Tn,∴cn=bn+1+bn+2+…+b2n+1
=1/(n+1)+1/(n+2)+…+1/(2n+1),
∴cn+1-cn=1/(2n+2)+1/(2n+3)-1/(n+1)
(1)a1=2,an=Sn-Sn-1=2n-1(n≥2).
∴bn={1/n (n≥2)
{2/3 (n=1)
(2)∵cn=T2n+1-Tn,∴cn=bn+1+bn+2+…+b2n+1
=1/(n+1)+1/(n+2)+…+1/(2n+1),
∴cn+1-cn=1/(2n+2)+1/(2n+3)-1/(n+1)