1/(1*3)+1/(3*5)+1/(5*7)+....1/(2011*2013)=(1-1/3)/2+(1/3-1/5)/2+(1/5-1/7)/2+......(1/2011-1/2013)/2=(1-1/3+1/3-1/5+1/5-1/7+......1/2011-1/2013)/2=(1-1/2013)/2=(2012/2013)/2=1006/2013祝学习进步。
