我的青春小鸟不回来:1/(1*2)+1/(2*3)+1/(3*4)+1/(4*5 )+...+1/(2000*2001)+1/(2001*2002)=

来源:百度文库 编辑:高考问答 时间:2024/07/04 20:07:32

1/2*3=1/2-1/3,1/3*4=1/3-1/4,...,
原式=1/1-1/2+1/2-1/3+1/3-1/4+...+1/2000-1/2001+1/2001-1/2002
=1-1/2002=2001/2002

2001/2002

原式=1-1/2+1/2-1/3……-1/2001+1/2001-1/2002=2001/2002

1/(1*2)+1/(2*3)+1/(3*4)+1/(4*5 )+...+1/(2000*2001)+1/(2001*2002)
=1-1/2+1/2-1/3+1/3-1/4+……+1/2001-1/2002
=1-1/2002
=2001/2002