1/2008-1/2007的绝对值+1/2007-1/2006的绝对值-1/2008-1/2006的绝对值
要有过程
1/2008-1/2007的绝对值+1/2007-1/2006的绝对值-1/2008-1/2006的绝对值
要有过程
1/2008-1/2007的绝对值+1/2007-1/2006的绝对值-1/2008-1/2006的绝对值
=1/2008+1/2007-1/2007+1/2006+1/2008-1/2006
=0
因为l1/2008-1/2007l<0,l1/2007-1/2006l<0,l1/2008-1/2006l<0
所以原式=1/2007-1/2008+1/2006-1/2007-1/2006+1/2008=0