x(1/1*2+1/2*3+1/3*4+……+1/2009*2010)=2009
x(1-1/2+1/2-1/3+13-1/4+……+1/2009-1/2010)=2006
x(1-1/2010)=2006
x(2009/2010)=2009
x=2010