(1\2+1\3)+(2\3+1\4)+(3\4+1\5)+(4\5+1\6)+......+(18\19+1\20)+(19\20+1\2)
来源:百度知道 编辑:UC知道 时间:2024/06/08 06:04:07
要有过程
去掉括号,得到
1/2+1/3+2/3+1/4+3/4+1/5+4/5+…+1/19+18/19+1/20+19/20+1/2
=1/2+(1/3+2/3)+(1/4+3/4)+1/5+4/5)+…+(1/19+18/19)+(1/20+19/20)+1/2
=1/2+1+1+1+…+1+1+1/2
=19
(1\2+1\3)+(2\3+1\4)+(3\4+1\5)+(4\5+1\6)+......+(18\19+1\20)+(19\20+1\2)
=1/2+(1/3+2/3)+(1/4+3/4)+(1/5+4/5)+...+(1/18+17/18)+(1/19+18/19)+(1/20+19/20)+1/2
=19
(1\2+1\3+...+1\2006)(1+1\2+1\3+...+1\2005)-(1+1\2+1\3+...+1\2006)(1\2+1\3+...+1\2005)
(1+1\2)*(1+1\3)*(1+1\3)*(1+1\4)*......(1+1\20)
3\1 3\1 3\1 3\1 3\1 =9\2
(1-1\2004)(1-1\2003)(1-1\2002).........(1-1\3)(1-1\2)
((1+1\2)(1+1\3)(1+1\4)(1+1\5)------(1+1\100))\(1-1\2)(1-1\3)(1-1\4)------(1-1\100)
((1+1\2)(1+1\3)(1+1\4)(1+1\5)------(1+1\100))\(1-1\2)(1-1\3)(1-1\4)------(1-1\100)等多少
[1+(-1\2)]+[1\2+(-1\3)]+[1\3+(-1\4)]+......[1\1999+(-1\2000)]
(1-1\2)+(1\2-1\3)+(1\3-1\4)+(1\4-1\5)+(1\5-1\6)+........(1\2005-1\2006
(1-1\2)+(1\2-1\3)+(1\3-1\4)+(1\4-1\5)+(1\5-1\6)+........(1\2005-1\20把括号变为绝对号咋么做06
1\1乘2+1\2乘3+...+1\2007乘2008