=1+3+5+7+9+11+13+15+1/3+1/15+……+1/195
=(1+15)*8/2+2*(1-1/3+1/3-1/5+1/5-1/7+……1/13-1/15)
=64+2*(1-1/15)
=64+28/15
=65又13/15