计算1/2000*2002+1/2002*2004+1/2004*2006+1/2006*2008+1/2008*2010

问题描述:

计算1/2000*2002+1/2002*2004+1/2004*2006+1/2006*2008+1/2008*2010

1/2×(1/2000-1/2002+1/2002-1/2004+……+1/2008-1/2010)=1/2×(1/2000-1/2010)=401/804000

原式=((1/2000-1/2002)+(1/2002-1/2004)+(1/2004-1/2006)+(1/2006-1/2008)+(1/2008-1/2010))/2
=(1/2000-1/2010)/2
=5/2000*2010
=5/4020000
=1/804000