(2/1*3/1)+(3/1*4/1)+(4/1*5/1)+....(2007/1*2008/1)的解法
来源:百度知道 编辑:UC知道 时间:2024/09/20 19:27:49
2/1*3/1=6/1=2/1-3/1
3/1*4/1=12/1=3/1-4/1
4/1*5/1=20/1=4/1-5/1
....
2007/1*2008/1=2007/1-2008/1
(2/1*3/1)+(3/1*4/1)+(4/1*5/1)+....(2007/1*2008/1)
=2/1-3/1+3/1-4/1+4/1-5/1......+2007/1-2008/1
=2/1-2008/1
=2008/1004-1=2008/1003
写错了吧:1/2*1/3+1/3*1/4+1/4*1/5+...+1/2007*1/2008=1/2-1/3+1/3-1/4+1/4-1/4+...+1/2007-1/2008=1/2-1/2008=1003/2008.
应该是(1/2*1/3)+(1/3*1/4)+(1/4*1/5)+....(1/2007*1/2008)吧
(1/2*1/3)+(1/3*1/4)+(1/4*1/5)+....(1/2007*1/2008)
=(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+....+(1/2007-1/2008)
=1/2-1/2008
=1003/2008
1+1/(1+2)+1/(1+2+3)+...+1/(1+2+3+...+100)
1+1/(1+2)+1/(1+2+3)+-------+1/(1+2+3+----+100)
1+1/2+1/3+.....+1/n
1+1/2+1/3+...+1/100
1-1/2+1/3-.....-1/10
(1+1/2+1/3+1/4)×
1+1/2+1/3+.....+1/2005][1/2+1/3+.......+1/2006]-[1/2+1/3+......+1/2005][1+1/2+1/3+1/2006]
(1-1/2-1/3-...-1/2001)*(1/2+1/3+...1/2002)-(1-1/2-1/3-...1/2002)*(1/2+1/3+...+1/2001)
1/1+2 + 1/1+2+3 +....+ 1/1+2+3+....+100=
(1/2005-1)(1/2004-1)........(1/3-1)(1/2-1)