原创2006年8月数学机井讨论稿第1遍（答案给出

scujean

2、  X, y, z三點在一條直線上面，y在x，z之間，w到x, z的距離相等，然後選下面那個必然成立。有
xw>xy;  xy>yz;  xw>yw等
  [解]選xw>yw
因為有兩種可能
x---y-w---z  或x---w-y--z
3、  （1）一個條件2的N次方=N的平方，（2）一個條件是N>0,問n的值。
[ans]DS題，選E，（1）不充分，N可為2，4

[此贴子已经被作者于2006-8-2 22:29:49编辑过]

skyinseas

大家看看答案有没有什么问题？

1.有一个图形体，两个同样大小的小圆一上一下斜放在一个正方形内和正方形相切，告诉小圆的半径，求正方形的对角线。

建议答案： 4r^2+2r

2.X, y, z三点在一条直线上面，y在x，z之间，w到x, z的具体相等，然后选下面那个必然成立有xw>xy; xy>yz; xw>yw等

建议答案：xy>yz;

3.一个条件2的N次方=N的平方，一个条件是N>0,问n的值。

建议答案： 4

4.(七月JJ)50millions people in 6 cities 那一道，人口最少的city的population给的不是百分比，而是2million,我差点看成2%了（人口第四多的city给的还是21%);

7月的原始题目是：

103. Divide 50 million population into 6 regions M N O P Q R in the sequence of from largest to smallest, where the number can be same, if R is 2 million, P is 21 percent of total, what is the maximum of Q.
       

 答案 6

5.(七月JJ)DS: M, N integers, is M^N integer? 1) N^M > 0; 2) N^M integer

答案：E

6.DS: appartments avg. rent $600, what is the percentage of appartments with rent under $600? 1) exactly half of the appartments with rent under $500; 2) the rents of differnt appartments are either $450, $550, $650, or $800.

建议答案：？

7.[(1+5^(1/2))/2]^2 + [(1-5^(1/2))/2]^2 = ?

答案：3

8.DS: right triangle, area = ? 1) sum of two shorter edge is 15; 2) longest edge is 12.

J建议答案：c

9.DS: formula for profit margin (M) for Sales (S) and Cost (C) is M = (S-C)/S, is M in 1999 more than 10% more than M in 1998? 1) S in 1999 is twice S in 1998; 2) C in 1999 is 50% more than C in 1998.

答案：好像是7月的机井 我选E

10. how many intersections can a triangle has with a circle? A) 1, 2, 3; B) 1, 2, 3, 6; C) 1, 2, , 4, 6; D) 1, 2, 3, 4, , 6; E) 1, 2, 3, 4, 5, 6

建议答案？

11.  DS: a line in x-y coordinate system goes through the origin and point (a,b), is a < b? 1) slope < 0; 2) a < 0 

建议答案：A

[此贴子已经被作者于2006-8-2 22:33:59编辑过]

scujean

4  DS: apartments avg. rent $600, what is the percentage of apartments with rent under $600? 1) exactly half of the apartments with rent under $500;  2) the rents of different apartments are either $450, $550, $650, or $800.
[解]選E嗎？
（1）只能知道[小於$600/全]>1/2
5. [(1+5^(1/2))/2]^2 + [(1-5^(1/2))/2]^2 = ?
利用（a+b）^2= a^2+b^2+2ab→a^2+b^2=（a+b）^2-2AB
[解]3
6. DS: right triangle, area = ? 1) sum of two shorter edge is 15; 2) longest edge is 12. [解]7月有遇到這題。選C。另兩短邊A B（1）a+b=15 （2）12^2=a^2+b^2
利用（a+b）^2= a^2+b^2+2ab 題目求1/2*AB

graceliuwang

ding

dasani

1.4r^2+2r

2.xw>yw (corrected)

3.E.since n can be equal to 2 or 4

[此贴子已经被作者于2006-8-2 22:58:38编辑过]

skyinseas

以下是引用dasani在2006-8-2 22:23:00的发言：

1.4r^2+2r

2.xy>yz

3.E.since n can be equal to 2 or 4

我知道了，画图就很好知道的[attachimg]49162[/attachimg]

[此贴子已经被作者于2006-8-2 22:42:55编辑过]

aprilfly

 

1.有一个图形体，两个同样大小的小圆一上一下斜放在一个正方形内和正方形相切，告诉小圆的半径，求正方形的对角线。

2a(根号2+2）a是小圆半径

2.X, y, z三点在一条直线上面，y在x，z之间，w到x, z的具体相等，然后选下面那个必然成立有xw>xy; xy>yz; xw>yw等

xw>yw

3.一个条件2的N次方=N的平方，一个条件是N>0,问n的值。

E

4.(七月JJ)50millions people in 6 cities 那一道，人口最少的city的population给的不是百分比，而是2million,我差点看成2%了（人口第四多的city给的还是21%);

6

5.(七月JJ)DS: M, N integers, is M^N integer? 1) N^M > 0; 2) N^M integer

E

6.DS: appartments avg. rent $600, what is the percentage of appartments with rent under $600? 1) exactly half of the appartments with rent under $500; 2) the rents of differnt appartments are either $450, $550, $650, or $800.

E

7.[(1+5^(1/2))/2]^2 + [(1-5^(1/2))/2]^2 = ?

4.5

8.DS: right triangle, area = ? 1) sum of two shorter edge is 15; 2) longest edge is 12.

C

9.DS: formula for profit margin (M) for Sales (S) and Cost (C) is M = (S-C)/S, is M in 1999 more than 10% more than M in 1998? 1) S in 1999 is twice S in 1998; 2) C in 1999 is 50% more than C in 1998.

E

10. how many intersections can a triangle has with a circle? A) 1, 2, 3; B) 1, 2, 3, 6; C) 1, 2, , 4, 6; D) 1, 2, 3, 4, , 6; E) 1, 2, 3, 4, 5, 6

E(切点也算交点的情况下）

11.  DS: a line in x-y coordinate system goes through the origin and point (a,b), is a < b? 1) slope < 0; 2) a < 0 

E

这是我的答案，欢迎大家讨论

skyinseas

以下是引用scujean在2006-8-2 22:15:00的发言：
5. [(1+5^(1/2))/2]^2 + [(1-5^(1/2))/2]^2 = ?
利用（a+b）^2= a^2+b^2+2ab→a^2+b^2=（a+b）^2-2AB
[解]3

我同意scujean的答案和解法

aprilfly

更正

1.（（根号2）+1））*2*a,a是小圆半径

7.3

skyinseas

以下是引用aprilfly在2006-8-2 22:48:00的发言：

更正

1.（（根号2）+1））*2*a,a是小圆半径

同意