二分之一加六分之一加十二分之一加二非常之一······加九非常之一=?
1/2+1/6+1/12+1/20+....+1/9900
=(1-1/2)+(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+...+(1/99-1/100)
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+...+1/99-1/100
=1-1/100
=99/100
0
1/2+1/6+1/12+1/20+....+1/9900
=(1-1/2)+(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+...+(1/99-1/100)
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+...+1/99-1/100
=1-1/100
=99/100