1/1x3+1/3x5+1/5x7.1/2009x2010+1/2011x2013

来源：学生作业帮助网编辑：作业帮时间：2024/05/14 07:19:10

1/1x3+1/3x5+1/5x7.1/2009x2011+1/2011x2013
=1/2×﹙1－1/3+1/3-1/5······+1/2009-1/2011+1/2011-1/2013)
=1/2×﹙1-1/2013﹚
=1006/2013