分类：教育/科学-学习帮助
问题：帮帮忙1/1x2x3+1/2x3x4+``````+1/98x9 
1/1x2x3+1/2x3x4+``````+1/98x99x100=?
回答：因为1/(x-1)x(x+1） =1/(x-1) +1/(x+1) -2/x
所以1/1x2x3+1/2x3x4+``````+1/98x99x100=
（1+1/3-2/2）+（1/2+1/4-2/3)+……+(1/98+1/100-2/99)=
1 - 1/2 - 1/99 + 1/100 =4949/9900