1+1/2+2/2+1/2+1/3+2/3+3/3

1个回答

=2*(1+1/2+2/2+1/3+2/3+3/3+...+1/100+2/100+...+100/100)-(1+2/2+3/3+...+100/100)
=2*(1+3/2+6/3+10/4+15/5+...101/2)-100
= (2+3+..+101)-100 =5050