放缩法:
A=1+1/2+(1/3+1/4)+(1/5+1/6+1/7+1/8)+(1/9+…+1/16)
>1+1/2+1/2+1/2+1/2=3(1)
因而,A>3
A=1+(1/2+1/3)+(1/4+1/5+1/6+1/7)+(1/8+1/9+…+1/16)
放缩法:
A=1+1/2+(1/3+1/4)+(1/5+1/6+1/7+1/8)+(1/9+…+1/16)
>1+1/2+1/2+1/2+1/2=3(1)
因而,A>3
A=1+(1/2+1/3)+(1/4+1/5+1/6+1/7)+(1/8+1/9+…+1/16)