1+1/3+1/6+1/10+1/4950
=1+1/2+1/10+1/4950
=1+6/10+1/4950
=1+2971/4950
=1又2971/49501/3到哪去了？1+1/3+1/6+1/10+1/15+......+1/4950 =2×（1/6+1/12+1/20+1/30+……+1/9900）+1=2×（1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+……+1/99-1/100）+1=2×（1/2-1/100）+1=1-1/50+1 =1又49/50上面1/3+1/6=1/2