哈哈,,,原来还漏掉几题~~也是怀疑GWD答案错了的,,,大家帮忙看看好么?

流浪猫猫2008

(1)

Does the decimal equivalent of P/Q, where P and Q are positive integers, contain only a finite number of nonzero digits?

(1)   P>Q 

(2)   Q=8

我选的答案是C,可是给的答案是E...

问题是,,,8作为除数,在它的被除数为1、2、3、4、5、6、7、8时，，，商的小数位分别为0.125、0.25、0.375、0.5、0.625、0.75、0.825、1啊...即所有的数的小数位都不会出现0的,但是只有当被除数>8时,,,才可以使各位以上都非负啊~~不是么?请教大家~~

(2)

If k=-1, which of the following is (are) true?

1. k^k=k  2. | k| =-k.   3.k^0=-k

 A. 1 only   B. 1 and 2 only   C. 1 and 3 only  

 D. 2 and 3 only    E.  1. 2. and 3.

我选了B,答案是E...

问题是,,,任何数的0次方应该是1吧,,,怎么可能为其本身呢?不是我记错了吧?~~

(3)

A certain carton holds fewer than 50 books. What is the number of books in the carton?

(1)   The books in the carton can be divided into 3 stacks of X books each, with 2 books left over.

(2)   The books in the carton can be divided into Y stacks of 7 books each, with 2 books left over.

这题我选了C,答案是E...

这题我算了很多遍了...设有M本书,,,M=3X+2,M=7X+2...通项公式为 M=21m+23,那么前提条件说了M<50的,所以在这个通项公式中,也只能使得题目要求的M值为44啊...并无他值了,,,因为其他满足该式的都使得M>50了~~可是怎么能选E呢?大家来看看好么?

juannner

(1)

Does the decimal equivalent of P/Q, where P and Q are positive integers, contain only a finite number of nonzero digits?

(1)   P>Q 

(2)   Q=8

选B. 问的是是否有有限非零的数. (即非无限循环小数). Q=8, 非零的数是有限的.

(2)

If k=-1, which of the following is (are) true?

1. k^k=k  2. | k| =-k.   3.k^0=-k

 A. 1 only   B. 1 and 2 only   C. 1 and 3 only  

 D. 2 and 3 only    E.  1. 2. and 3.

应该是E.

k^0=1=-k

(3)

A certain carton holds fewer than 50 books. What is the number of books in the carton?

(1)   The books in the carton can be divided into 3 stacks of X books each, with 2 books left over.

(2)   The books in the carton can be divided into Y stacks of 7 books each, with 2 books left over.

选E

M=3X+2,M=7X+2...

M可以是23本, 或者44本.

流浪猫猫2008

谢谢2楼的同学,,,第2\3题我弄懂了,,,可是第1题...第1题我怎么看怎么觉得它在问contain only a finite number of nonzero digits=有限位的小数,且每个数位上都非0,那么怎么不把个位也包括在内呢?

继续请教~~