1/1x2+1/3x4+1/4x5+L+1/2008x2009
问题描述:
1/1x2+1/3x4+1/4x5+L+1/2008x2009
第一个份数和第二个份数之间是少了1/2x3这个数的
答
原式=1-1/2+1/3-1/4+1/4-1/5+……+1/2008-1/2009
=1-1/2+1/3-1/2009
=10039/12054