1/30+1/42+1/56+1/72+1/90

来源:学生作业帮助网 编辑:六六作业网 时间:2024/12/29 16:52:33
1/30+1/42+1/56+1/72+1/901/30+1/42+1/56+1/72+1/901/30+1/42+1/56+1/72+1/901/30+1/42+1/56+1/72+1/90=(1/

1/30+1/42+1/56+1/72+1/90
1/30+1/42+1/56+1/72+1/90

1/30+1/42+1/56+1/72+1/90
1/30+1/42+1/56+1/72+1/90
=(1/5-1/6)+(1/6-1/7)+(1/7-1/8)+(1/8-1/9)+(1/9-1/10)
【中间的一些项可以前后抵消】
=1/5-1/10
=1/10

5455555分之一