推 NightCat427:謝謝你，第一題講得很清楚 :) 12/31 06:58
※ 引述《NightCat427 (寵愛，盡在不言中)》之銘言：
: 1.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 E
: 2.If x, y, and z are integers and xy+z is an odd integer, is x an even integer?
: (1) xy+xz is an even integer
: (2) y+xz is an odd integer
: 答案 A
1.你可以先變成 (2^50(50!)+1)/p 可以看出來2^50(50!)的質因數2 3 5 7...47
但是他又加一個1所以47以下的質因數都不能整除(2^50(50!)+1)
因此最小的質因數一定是大於47
2.我不確定 我是把(xy+xz)-(xy+z)=z(x-1)
even-odd --->odd 所以x-1是odd 所以x是even
利用二好像得不到什麼結果
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 147.31.212.129