1/3+1/6+1/10+1/15+1/21+```````+1/105+1/120

来源：学生作业帮助网编辑：六六作业网时间：2025/01/20 00:55:11

1/3+1/6+1/10+1/15+1/21+```````+1/105+1/1201/3+1/6+1/10+1/15+1/21+```````+1/105+1/1201/3+1/6+1/10+1/1

1/3+1/6+1/10+1/15+1/21+```````+1/105+1/120
1/3+1/6+1/10+1/15+1/21+```````+1/105+1/120

1/3+1/6+1/10+1/15+1/21+```````+1/105+1/120
1/3+1/6+1/10+1/15+1/21+```````+1/105+1/120
=1/2(1/2-1/3+1/3-1/4+…………+1/15-1/16)
=1/2(1/2-1/16)
=7/32

1/3+1/6+1/10+1/15+1/21+```````+1/105+1/120
=2(1/2-1/3+1/3-1/4+…………+1/15-1/16)
=2(1/2-1/16)
=7/8