作业帮1\2+1\6+1\12+1\20+1\30+1\42+1\7
来源：学生作业帮助网 编辑：作业帮 时间：2024/04/29 06:14:17
1\2+1\6+1\12+1\20+1\30+1\42+1\7
1\2+1\6+1\12+1\20+1\30+1\42+1\7
1\2+1\6+1\12+1\20+1\30+1\42+1\7
1\2+1\6+1\12+1\20+1\30+1\42+1\7
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7
=1
1\2+1\6+1\12+1\20+1\30+1\42+1\7
=1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7
=1
1\2+1\6+1\12+1\20+1\30+1\42+1\7
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7
=1
1
=4/6+1/12+1/20+1/30+1/42+1/7=9/12+5/60+7/42=1
1