(1/2009-1/2008)的绝对值+(1/2008-1/2007)的绝对值+(1/2007-1/2006)的绝对值...+(1/3分之一-1/2)的绝对值+(1/2-1 )
=(1/2008-1/2009)+(1/2007-1/2008)+(1/2006-1/2007)+...+(1/3-1/4)+(1/2-1/3)+(1-1/2)
=(1-1/2))+(1/2-1/3)+(1/3-1/4)+...+(1/2006-1/2007)+(1/2007-1/2008)+(1/2008-1/2009)
=1-1/2009
=2008/2009