因为 (1/2*3/4*5/6*7/8*...*99/100)*(2/3*4/5*6/7*...*98/99)
=1/100
2/3*4/5*6/7*...*98/99>2/3*4/5*6/7*...*98/99*100/101
>1/2*3/4*5/6*7/8*...*99/100
所以(1/2*3/4*5/6*7/8*...*99/100)*(1/2*3/4*5/6*7/8*...*99/100)
<(1/2*3/4*5/6*7/8*...*99/100)*(2/3*4/5*6/7*...*98/99)
则1/2*3/4*5/6*7/8*...*99/100<1/10