[原创] 十月十日 数学机井更新至五十四

mrjj

51. In the figure shown above, if line y=c divided the triangle
equally, c=?
 4-2√2　　

这题不会，能解释下么？　平分是什么意思？　为什么不是４的一半呢？

谢谢

mrjj

 54. For integer n, f(n) denotes the remainder when n is divided by
integer k. Is k greater than 10?
 1). f(k+32)=8
 2). f(k+42)=6
 A

这个题也不知道从何下手，ＹＡＯＭＡＯ能说说思路吗？

惭愧，下星期就要考了

powerlich

顶

powerlich

0/1----------------------------------------1/1
 0/1----------------1/2---------------------1/1 
 0/1-------1/3------1/2---------2/3--------1/1
 0/1  1/4  1/3 2/5  1/2  3/5   2/3   3/4  1/1

42. As the figures shows, after the first line, the number of fractions
in each of the following lines increased. The denominator of the added number
is the sum of the denominators of the up-right and up-left fractions, and so
does the numerator, for example, 1/4=0+1/1+3. Which line will contain 6/11 and
5/9?

1/2 作为中间位置不变。以1/2为中心展开。

4行：2/5   1/2    3/5

5 line: 3/7 1/2 4/7

6 line: 4/9 1/2 5/9

7 line: 5/11 1/2  6/11

因为7 行包括所6行数据，所以答案：7

JJ总结第57题 引用talksky的回帖 请讨论

floridaus

50. The sum of the integers from 1 to n is n(n+1)/2. What is the sum of
the even numbers between 99 and 301?

Choices include (301*302/2-99*100/2)/2 ?E/P> 
 101（100+300）/2=20200
 

请教

mc637t

54解法

F(k+32)餘8:即(k+32)/K=(K/K)+(32/K)餘8,因(K/K)整除,故餘數必出現在(32/K)中

因為餘8,所以K必整除(32-8)=24,且K為24的因數且K>8.所以K=12,24>10,故成立

同理F(k+42)餘6:k為36的因數且K>6,所以K=9,12,18,36不完全>10,不成立

答案A

想桐桐的蝎子

都是NN，希望我也能好运。。。。

[此贴子已经被作者于2006-10-11 20:55:13编辑过]

sinoversion

thx