简便计算
1/3+1/15+1/35+.+1/4040099
=1/1x3+1/3x5+1/5x7+...+1/2009x2011
=1/2(1-1/3)+1/2(1/3-1/5)+1/2(1/5-1/7)+...+(1/2009-1/2011)
=1/2(1-1/2011)
=1005/2011
1/3+1/15+1/35+.+1/4040099
简便计算
1/3+1/15+1/35+.+1/4040099
=1/1x3+1/3x5+1/5x7+...+1/2009x2011
=1/2(1-1/3)+1/2(1/3-1/5)+1/2(1/5-1/7)+...+(1/2009-1/2011)
=1/2(1-1/2011)
=1005/2011