Question

x/1*3+x/3*5+…x/2007*2009=2009的过程和解

Answer 1

x/1*3=x/2*(1/1-1/3,其它数一样,

x/1*3+x/3*5+…x/2007*2009＝x/2*(1-1/3+1/3-1/5...+1/2007-1/2009)=x/2*(1-1/2009)=2009,得x＝2009^2/1004