两边取对数有：lnF(x)=lnx+ln(x+1)+....+ln(x+2009)，则F'(X)/F(x)=[1/x+1/(x+1)+...+1/(x+2009)]，从而就有F'(X)=[1/x+1/(x+1)+...+1/(x+2009)]*F(x)
