神舟k550d:30/1+42/1+56/1+72/1+90/1=?
来源:百度文库 编辑:杭州交通信息网 时间:2024/10/06 17:55:10
请写出主要过程.
哦,错了.
应该是1/30+1/42+1/56+1/72+1/90=?
哦,错了.
应该是1/30+1/42+1/56+1/72+1/90=?
是1/30+1/42+1/56+1/72+1/90吧
1/30+1/42+1/56+1/72+1/90
=1/(5*6)+1/(6*7)+1/(7*8)+1/(8*9)+1/(9*10)
=1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9+1/9-1/10
=1/5-1/10
=1/10
不会吧?这个还需要过程么?直接相加啊。
290
是输入错了吗?这不就是
30+42+56+72+90=290吗??
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
=2/10-1/10
=1/10
是1/30+1/42+1/56+1/72+1/90吧等于1/10
=84/2520+60/2520+45/2520+35/2520+28/2520
=252/2520
=1/10
巧算 1/30+1/42+1/56+1/72+1/90
30/1+42/1+56/1+72/1+90/1=?
20/1+30/1+42/1+56/1+72/1+90/1
1/20+1/30+1/42+1/56+1/72+1/90
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90=
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90=?
1/22+1/30+1/42+1/56+1/72+1/90=?简便方法是什么?
谁能巧算1-1/2-1/6-1/12-1/20-1/30-1/42-1/56-1/72-1/90
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90=______
1/30+1/42+1/72+1/90+…1/9900