搜搜做题作业网11*10*2
来源：学生作业帮 编辑：搜搜做题作业网作业帮 分类：数学作业 时间：2024/07/05 23:59:05
11*10*2
把an通项公式带进去
Tn=1/3*5+……+1/(2n+1)(2n+3)
=1/2(1/3-1/5+……+1/2n+1-1/2n+3)
=1/2(1/3-1/2n+3)
=n/6n+9
Tn=1/3*5+……+1/(2n+1)(2n+3)
=1/2(1/3-1/5+……+1/2n+1-1/2n+3)
=1/2(1/3-1/2n+3)
=n/6n+9