you could be my world:一道数学题

来源:百度文库 编辑:高考问答 时间:2024/05/12 00:44:12
1/1*2+1/2*3+1/3*4+1/4*5+A+1/98*99+1/99*100等于( )
(题中/为分号)谢谢!

=1-1/2+1/2-1/3+1/3-1/4...+1/99-1/100=99/100

因为1/(1*2)=1/2=1-1/2
同理
1/(2*3)=1/2-1/3

1/n(n+1)=1/n-1/(n+1)
得1-1/2+1/2-1/3+1/3-1/4...+1/99-1/100=99/100