2/(X+1)(X+2)+2/(X+3)(X+5)+2/(X+5)(X+7)----+2/(X+2007)(X+2009)=

显示全部楼层 · 2013-4-16 08:25:25

按照规律，你的题目第一个应该是2/(X+1)(X+3)吧~我按照改过来的计算：2/(X+1)(X+3)+2/(X+3)(X+5)+2/(X+5)(X+7)----+2/(X+2007)(X+2009)=1/(x+1)-1/(x+3)+1/(x+3)-1/(x+5)+.....1/(x+2007)-1/(x+2009)=1/(x+1)-1/(x+2009)=2008/(x+1)(x+2009)...

千问 · 2013-4-16 08:25:25

2/(X+1)(X+3)+2/(X+3)(X+5)+2/(X+5)(X+7)----+2/(X+2007)(X+2009)=1/(x+1)-1/(x+3)+1/(x+3)-1/(x+5)+.....+1/(x+2007)-1/(x+2009)=1/(x+1)-1/(x+2009)=2008/[(x+1)(x+2009)]...

千问 · 2013-4-16 08:25:25

2/(X+3)(X+5)+2/(X+5)(X+7)----+2/(X+2007)(X+2009)=1/(X+3)-1/(X+5)+…+1/(X+2007)-1/(X+2009)=1/(X+3)-1/(X+2009) 原式=2/(X+1)(X+2)+1/(X+3)-1/(X+2009)...

千问 · 2013-4-16 08:25:25

如果第一项是2/(x+1)(x+3)的话结果为1/(x+1) - 1/（x+2009）用裂项的方法解的2/(x+1)(x+3)=1/(x+1) - 1/（x+3）...

千问 · 2013-4-16 08:25:25

2/(X+1)-2/(X+2009)...