17)
http://i729.photobucket.com/albums/ww291/kaka1307/0384-1.jpg
ans
a)2,3,4
b) 19/240
13)
http://i729.photobucket.com/albums/ww291/kaka1307/0381-1.jpg
ans: 18,272
pls show clear steps.
F.5 trigo& probability
2011-07-24 3:12 am
回答 (1)
2011-07-24 4:05 am
✔ 最佳答案
17(a) C(16,2) = 120C(x,2)/120 < 1/12
x(x - 1) < 20
=> x = 2,3,4
(b) Take x = 4
The probability = C(4,3)/C(16,3) + C(4,2)C(12,1)/C(16,3) = 19/140
13 1/(tanx)^2 + 4/tanx - 21 = 0
21y^2 - 4y - 1 = 0 (where y = tanx)
(3y - 1)(7y + 1) = 0
y = 1/3 or -1/7
x = 18 or 172
收錄日期: 2021-04-26 19:16:29
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20110723000051KK00845