求助PREP 1 道数学题

georgeqian

1. For every positive even integer n, the fuction 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 1o

E.greater than 40

answer:E

albertjerrys

h(100)+1与h(100)互质，h(100)=2*4*……*100=2^50*(1*2*……*49*50)

h(100)的质因数包括所以小于50的质数，h(100)+1肯定不含这些质因数，最小的是51

georgeqian

thanks @@@@@@@@@@@@@