Prep07数学错题疑问集ps（1）【至5.15未解答状态1/19】

灵狩Icy

第十二题：
http://forum.chasedream.com/foru ... amp;fromuid=1055392

灵狩Icy

第13题：
http://forum.chasedream.com/foru ... ;extra=#pid21736766

lululuna

14. For all positive integers m,  【m】 = 3m， when m is odd and m = 1/2 m ，when m is even.  Which of the following is equivalent to 【9】 x 【6】  ?

注意黄色部分，题主你是不是抄错题目了，M是正整数，你的【1/2】显然不符合题意啊

解答：
【9】,9是奇数，所以【9】=9*3=27

【6】,6是偶数，所以【6】=1/2*6=3；

综上【9】*【6】=27*3=【27】

灵狩Icy

lululuna 发表于 2015-5-13 14:22
14. For all positive integers m,  【m】 = 3m， when m is odd and m = 1/2 m  ...

原来如此，我说怎么哪里不对劲。。谢谢啦！！

灵狩Icy

17、18题：iriswine
http://forum.chasedream.com/foru ... ;page=1#pid21739388

灵狩Icy

18，19题
http://forum.chasedream.com/thread-1002744-1-1.html

virnnie

觉得15题必须要有个图，看一下，到底那个圆跟三角形是什么关系啊。

lyllillian

多谢~~~~~~~~~~~~~~

三条

80. if r and s are integers and rs + r is odd, which of the following must be even?  
A) r
b) S
c) r+s
d) rs - s  
e)  r^2 + s   

答案B
为什么不选 d 呢？ rs-s = (r-1)s  也是even阿，求高手解答

TTTTTina.Wong

How many different prime numbers are factors of the positive integer n ?
(1) Four different prime numbers are factors of 2n.
(2) Four different prime numbers are factors of n^2.

求问！