Question

请问这道题怎样解算：（1+1/2+1/+L+1/2007)*(1/2+1/3+L+1/2008)-(1+1/2+L+1/

Answer 1

设1+1/2+1/3+.+1/2008=a

(a-1/2008)(a-1)-a(a-1-1/2008)=1/2008