1/2*3+1/3*4+1/4*5+1/5*6.+1/19*20

来源：学生作业帮助网 编辑：作业帮 时间：2024/05/08 15:56:57
1/2*3+1/3*4+1/4*5+1/5*6.+1/19*20

1/2*3+1/3*4+1/4*5+1/5*6.+1/19*20
1/2*3+1/3*4+1/4*5+1/5*6.+1/19*20

1/2*3+1/3*4+1/4*5+1/5*6.+1/19*20
1/2*3+1/3*4+1/4*5+1/5*6.+1/19*20
=1/2-1/3+1/3-1/4+...+1/19-1/20
=1/2-1/20
=9/20

1-1/20=19/20