1/2+1/3+2/3+1/4+2/4+3/4+……+1/60+2/60+3/60……+58/60+59/60=
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/24 23:58:21
![1/2+1/3+2/3+1/4+2/4+3/4+……+1/60+2/60+3/60……+58/60+59/60=](/uploads/image/z/13389-69-9.jpg?t=1%2F2%2B1%2F3%2B2%2F3%2B1%2F4%2B2%2F4%2B3%2F4%2B%E2%80%A6%E2%80%A6%2B1%2F60%2B2%2F60%2B3%2F60%E2%80%A6%E2%80%A6%2B58%2F60%2B59%2F60%3D)
1/2+1/3+2/3+1/4+2/4+3/4+……+1/60+2/60+3/60……+58/60+59/60=
1/2+1/3+2/3+1/4+2/4+3/4+……+1/60+2/60+3/60……+58/60+59/60=
1/2+1/3+2/3+1/4+2/4+3/4+……+1/60+2/60+3/60……+58/60+59/60=
1/n+2/n+3/n+.(n-1)/n=(1+2+3+.n-1)/n=(n-1)/2
1/2+1/3+2/3+1/4+2/4+3/4+……+1/60+2/60+3/60……+58/60+59/60
=1/2+(3-1)/2+(4-1)/2+.+(60-1)/2
=(1+2+3.+59)/2
=60*59/4
=885