数学GWD特别不解的一道题，求求大神

苦海里的小乌龟

Q17:

file:///C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/msohtml1/03/clip_image001.gif

图另外传上了

In the figure, points A, B, C, D, and E lieon a line.  A is on both circles, B isthe center of the smaller circle, C is the center of the larger circle, D is onthe smaller circle, and E is on the larger circle.  What is the area of the region inside thelarger circle and outside the smaller circle?

(1)     AB =3 and BC =2

(2)     CD =1and DE = 4

                  

A. Statement (1) ALONE issufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE issufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHERare sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE issufficient.

E. Statements (1) and (2) TOGETHERare NOT sufficient.

Answer: 为什么不选D呢，答案是A，我觉得2也可以吧

zongziphoto

确实可以求出来 我觉得选D

soho92

zongziphoto 发表于 2013-6-1 04:21
确实可以求出来 我觉得选D

2怎么算出来的？？

zongziphoto

CD=1, DE=4，那么大圆的半径R=CE=5， 所以直径AE=10
所以小圆的直径AD=AE-DE=6
故小圆半径r=3
R和r都知道了自然可以求出来

zongziphoto

soho92 发表于 2013-5-31 22:52
2怎么算出来的？？

回复错地方了。。。

CD=1, DE=4，那么大圆的半径R=CE=5， 所以直径AE=10
所以小圆的直径AD=AE-DE=6
故小圆半径r=3
R和r都知道了自然可以求出来

苦海里的小乌龟

zongziphoto 发表于 2013-6-1 13:58
CD=1, DE=4，那么大圆的半径R=CE=5， 所以直径AE=10
所以小圆的直径AD=AE-DE=6
故小圆半径r=3

大神，答案是选D吧？可是我做了不止一次的答案都说要选A，阿西巴！

zongziphoto

zongziphoto 发表于 2013-6-1 08:05
回复错地方了。。。

CD=1, DE=4，那么大圆的半径R=CE=5， 所以直径AE=10

没有问题 就选D
OG上有原题

看下面这个链接：
http://books.google.fr/books?id=sQW_fKaYR4QC&pg=PA328&lpg=PA328&dq=In+the+figure,+points+A,+B,+C,+D,+and+E+lie+on+a+line.%C2%A0%C2%A0A+is+on+both+circles,+B+is+the+center+of+the+smaller+circle,+C+is+the+center+of+the+larger+circle,+D+is+on+the+smaller+circle,+and+E+is+on+the+larger+circle&source=bl&ots=DypSA-1c0H&sig=S9gLdkx-IAd_LhHsvRWwHSXzK0A&hl=zh-CN&sa=X&ei=5CeqUZGjCaG40QWK4IDgDQ&ved=0CFsQ6AEwBA#v=onepage&q=In%20the%20figure%2C%20points%20A%2C%20B%2C%20C%2C%20D%2C%20and%20E%20lie%20on%20a%20line.%C2%A0%C2%A0A%20is%20on%20both%20circles%2C%20B%20is%20the%20center%20of%20the%20smaller%20circle%2C%20C%20is%20the%20center%20of%20the%20larger%20circle%2C%20D%20is%20on%20the%20smaller%20circle%2C%20and%20E%20is%20on%20the%20larger%20circle&f=false

安心思密达~