1、Sn=3n^2-2n
则An=Sn-S(n-1)=6n-5
2、Bn=3/An*An+1=3/(6n-5)(6n+1)=1/2[1/(6n-5)-1/(6n+1)] (裂项相消即可)
故Tn=1/2[1-1/7+1/7-1/13+……+1/(6n-5)-1/(6n+1)]
=1/2[1-1/(6n+1)]
=3n/(6n+1)
1、Sn=3n^2-2n
则An=Sn-S(n-1)=6n-5
2、Bn=3/An*An+1=3/(6n-5)(6n+1)=1/2[1/(6n-5)-1/(6n+1)] (裂项相消即可)
故Tn=1/2[1-1/7+1/7-1/13+……+1/(6n-5)-1/(6n+1)]
=1/2[1-1/(6n+1)]
=3n/(6n+1)