prep上一道 h(100)的书学题 求NN来解答啊~~~马上要考了额

lorolana

For every positive integer n, the function h(n) is defined to be the product of all even integer from 2 to n, inclusive, if p is the smallest prime factor of h(100)+1, then P is

A between 2-10
B  .............10-20
C ..............20-30
D...............30-40
E greater than 40

答案是:E  为什么啊。。。尊的米思路哦。。。

jinke0123

哈，我昨天发一贴，也是这个没的NN理我

纪纪

H(100)+1=(2*4*6*8*.....*100)+1=2(1*2*3*4*....*50)+1
由于相邻两个数互质，所以 1到50都不可能是h(100)+1的因子
也就是说最小质因子一定大于50 所以选E

尹咖喱

http://forum.chasedream.com/GMAT_Math/thread-532876-1-1.html

lorolana

多谢啊~看到NN的解释了~~