1/1*2*3+1/2*3*4+1/3*4*5+.+1/8*9*10
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/27 11:14:34
![1/1*2*3+1/2*3*4+1/3*4*5+.+1/8*9*10](/uploads/image/z/3992431-31-1.jpg?t=1%2F1%2A2%2A3%2B1%2F2%2A3%2A4%2B1%2F3%2A4%2A5%2B.%2B1%2F8%2A9%2A10)
1/1*2*3+1/2*3*4+1/3*4*5+.+1/8*9*10
1/1*2*3+1/2*3*4+1/3*4*5+.+1/8*9*10
1/1*2*3+1/2*3*4+1/3*4*5+.+1/8*9*10
1/1*2*3+1/2*3*4+1/3*4*5+.+1/8*9*10
=1/2*(1/1*2-1/2*3+1/2*3-1/3*4+1/3*4-1/4*5+.+1/8*9-1/9*10)
=1/2*(1/1*2-1/9*10)
=1/2*(1/2-1/90)
=1/2*22/45
=11/45