请教一道数学题

YUNBU · 发表于 2010-4-1 22:12:57

7。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

davidleezone · 发表于 2010-4-1 22:28:05

h(100)+1的prime factor 一定能被它整除，f(100)是100的阶乘， 100以内的任何一个数除f(100)+1的余数都是1，也就是说能被f(100)+1整除的数肯定要大于100，它的smallest prime factor 肯定大于 100！

不知道解释清楚了没有~

fay009 · 发表于 2010-4-1 22:32:15

思路和楼上差不多。。但是我觉得是只要大于50就可以了~~

请教一道数学题

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