1/1*2+1/2*3+1/3*4+……+1/2004*2005+1/2005*2006 1/1*3+1/3*5+1/5*7+……+1/49*51

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/02 18:21:03
1/1*2+1/2*3+1/3*4+……+1/2004*2005+1/2005*2006 1/1*3+1/3*5+1/5*7+……+1/49*51

1/1*2+1/2*3+1/3*4+……+1/2004*2005+1/2005*2006 1/1*3+1/3*5+1/5*7+……+1/49*51
1/1*2+1/2*3+1/3*4+……+1/2004*2005+1/2005*2006 1/1*3+1/3*5+1/5*7+……+1/49*51

1/1*2+1/2*3+1/3*4+……+1/2004*2005+1/2005*2006 1/1*3+1/3*5+1/5*7+……+1/49*51
1/1*2+1/2*3+1/3*4+……+1/2004*2005+1/2005*2006
=1-1/2+1/2-1/3+1/3-1/4+……+1/2005-1/2006
=1-1/2006
=2005/2006
1/1*3+1/3*5+1/5*7+……+1/49*51
=1/2*(2/1*3+2/3*5+2/5*7+……+2/49*51)
=1/2*(1-1/3+1/3-1/5-1/5-1/7+……+1/49-1/51)
=1/2*(1-1/51)
=25/51

(1)原式=1-1/2+1/2-1/3+1/3-1/4+……-1/2005+1/2005-1/2006=1-1/2006=2005/2006
(2)原式=1/2(1-1/3+1/3-1/5+1/5-……-1/49+1/49-1/51)=1/2(1-1/51)=25/51

1、可以分成1-1/2+1/2-1/3+.....+1/2004-1/2005+1/2005-1/2006=1-1/2006=2005/2006

1/1*2+1/2*3+1/3*4+......+1/2004*2005+1/2005*2006
=1-1/2+1/2-1/3+.....+1/2005-1/2006=1-1/2006
=2005/2006

1/1*3+1/3*5+1/5*7+……+1/49*51
=1/2(1-1/3)+1/2(1/3-1/5)+1/2(1/5-1/7)+......+1/2(1/49-1/51)
=1/2(1-1/3+1/3-1/5+1/5-1/7+........+1/49-1/51)
=1/2(1-1/51)
=1/2*50/51
=25/51

数字打出来不方便。