1/2+1/6+1/12...越快越好!
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/03 22:40:24
![1/2+1/6+1/12...越快越好!](/uploads/image/z/5150843-35-3.jpg?t=1%2F2%2B1%2F6%2B1%2F12...%E8%B6%8A%E5%BF%AB%E8%B6%8A%E5%A5%BD%21)
1/2+1/6+1/12...越快越好!
1/2+1/6+1/12...
越快越好!
1/2+1/6+1/12...越快越好!
原式=1*1/2+1/2*1/3+1/3*1/4+1/4*1/5.+1/10*1/11
=1-1/2+1/2-1/3+1/3-1/4.+1/10-1/11
=1-1/11
=10/11
1/n(n-1)=1/n-1 -1/n
1/2+1/6+1/12...+1/110=1-1/2+1/2-1/3......-1/11=10/11
10/11
=1*1/2+1/2*1/3+1/3*1/4+1/4*1/5.....+1/10*1/11
=1-1/2+1/2-1/3+1/3-1/4......+1/10-1/11
=1-1/11
=10/11