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
答案是E
h(100)+1=2x4x6x8....x100=2^50*50!+1
50!可以被50以内的任何一个正整数整除,h(100)+1被1-50任何一个整除后余1
所以没有小于50的质因子
欢迎光临 国际顶尖MBA申请交流平台--TOPWAY MBA (http://forum.topway.org/) | Powered by Discuz! 7.2 |