标题: 求问一道prep的数学 [打印本页] 作者: chenyuchen13 时间: 2012-1-14 18:57 标题: 求问一道prep的数学 For every positive even integer n, thefunction h(n) is defined to be the product of all the even integers from 2 ton, 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，智商有限，求解答！作者: justabeginning 时间: 2012-1-14 19:23
2*4*6......*100=2^50*50! 因为相邻的两个数没有除一以外相同的因子，所以从2-50都不会是h(100)+1的因子，因此smallest prime 一定大于50，因此选E