3/2000×2001+3/2001×2002+3/2002×2003+……+3/2009×2010+3/2010×2011
=3(1/2000-1/2001+1/2001-1/2002+1/2002-1/2002+……+1/2009-1/2010+1/2010-1/2011)
=3(1/2000-/2012)
=33/4024000
3/2000×2001+3/2001×2002+3/2002×2003+……+3/2009×2010+3/2010×2011
=3(1/2000-1/2001+1/2001-1/2002+1/2002-1/2002+……+1/2009-1/2010+1/2010-1/2011)
=3(1/2000-/2012)
=33/4024000