已知XY的值,求1/xy+1/(x+1)(y+1)++……+1/(x+2006)(y+20006)的值。快!!!
来源:百度知道 编辑:UC知道 时间:2024/07/07 20:59:04
已知XY的值分别为1,2,求1/xy+1/(x+1)(y+1)+1/(x+2)(y+2)+……+1/(x+2006)(y+20006)的值.
有急用,答得好有追加!!!!!!!!!!!!!!!1
快!!!!!!!!!!!!!!!!!!!
拜托了,过程也要有!!!!!!!!!
不好意思~~!原题是2006,不是20006!
有急用,答得好有追加!!!!!!!!!!!!!!!1
快!!!!!!!!!!!!!!!!!!!
拜托了,过程也要有!!!!!!!!!
不好意思~~!原题是2006,不是20006!
1/xy+1/(x+1)(y+1)++……+1/(x+2006)(y+20006)
= 1-1/2 + 1/2-1/3 +... + 1/2007 -1/2008
=2007/2008
原题中的1/(x+2006)(y+20006)
改为1/(x+2006)(y+2006),不是20006,
1/2=1-1/2,
1/2*3=1/2-1/3,
1/3*4=1/3-1/4,
... ...
1/xy+1/(x+1)(y+1)++……+1/(x+2006)(y+2006)
=1/1*2+1/(1+1)(2+1)++……+1/(1+2006)(2+2006)
=1/2+1/2*3+1/3*4+... ... +1/2007*2008
=1-1/2+1/2-1/3+... ... +1/2007-1/2008
=1-1/2008
=2007/2008
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