【高中数学-数列】【回答后加20分,防止题目作废】数列{an}满足an=2n-1,bn=ln（1+1/an）

1/2 ln an+1=1/2ln(2n+1),bn=ln(1+1/2n-1),首先易证(2/1）x(4/3)x(6/5)x.2n/(2n-1)>(3/2)x(5/4)x(7/6)x.(2n+1/2n),Tn=1n(2/1)+1n(4/3)+.1n(2n/(2n-1))=1n[(2/1）x(4/3)x(6/5)x.2n/(2n-1)]所以,1n[(2/1）x(4/3)x(6/5)x.2n/(2n-1)]^2>1n[(2/1）x(3/2)x（4/3）x(5/4)x.2n/(2n-1)x(2n+1)/2n]=1n(2n+1),即2ln[(2/1）x(4/3)x(6/5)x.2n/(2n-1)]>1n(2n+1)即ln[(2/1）x(4/3)x(6/5)x.2n/(2n-1)]>(1/2)1n(2n+1),即Tn>(1/2)1n(an+1).