prep(一)数学第7题

7. 905-!-item-!-187;#058&000575     为什么选E呢?没有头绪
For every positive even integer n, the function h(n) is defined to be the product of all the even integers from 2 to n, inclusive.  If p is the smallest prime factor of h(100) + 1, then p is

(A) between 2 and 10
(B) between 10 and 20
(C) between 20 and 30
(D) between 30 and 40
(E) greater than 40

E

2*4*.....*100+1=2^50*50!+1

2^50*50!是50以内的任意质数的整数倍，所以再加上一就不可能是其整数倍，故该质约数一定比50还大

明白了，谢谢：）