1/2+1/6+1/12+1/20+1/30+1/40+1/42+1/56+1/72
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/28 10:14:35
![1/2+1/6+1/12+1/20+1/30+1/40+1/42+1/56+1/72](/uploads/image/z/3834592-16-2.jpg?t=1%2F2%2B1%2F6%2B1%2F12%2B1%2F20%2B1%2F30%2B1%2F40%2B1%2F42%2B1%2F56%2B1%2F72)
1/2+1/6+1/12+1/20+1/30+1/40+1/42+1/56+1/72
1/2+1/6+1/12+1/20+1/30+1/40+1/42+1/56+1/72
1/2+1/6+1/12+1/20+1/30+1/40+1/42+1/56+1/72
=1-1/2+1/2-1/3+1/3-1/4+…+1/7-1/8+1/8-1/9 =1-1/9 =8/9 怎么中间还有个1/40啊?题抄得对吧?如果有再加个1/40 这个题的规律是 1/2=1-1/2 1/6=1/2-1/3 …… 1/72=1/8-1/9