数学T paper 2讨论专区

白羊座aries

（减，加）-->左边号码小，右边号码大

不可以搞乱秩序..
乙劍真人 发表于 25-5-2010 09:05 PM

   
无论怎么说都好，已经失去一半的分数了.

乙劍真人

无论怎么说都好，已经失去一半的分数了.
白羊座aries 发表于 25-5-2010 09:08 PM

没关系，已经过去了..

到正式考试就不会再丢分了..^^

csleu89

Help to solve:
The position vectors of the points A,B,C with respect to origin O, are a , b and c respectively. L ,M,P,Q midpoint of OA,BC,OB and AC.
(a) Show that the position vector of any point on the line LM is 1/2a+1/2m(b+c-a) for some scalar of m and express the position vector of any points on the line PQ in terms of a,b and c.
(b) Find the position veector of the point of intersection of the line LM and the line PQ.

walrein_lim88

Help to solve:
The position vectors of the points A,B,C with respect to origin O, are a , b and c r ...
csleu89 发表于 26-5-2010 03:30 PM

willyisstupid

回复 277# 白羊座aries


that one show A and B' are independent if A and B are independent
from P(AnB) = P(A)xP(B)
then you wanna see whether A and B' are independent
so you start with
P(A)xP(B')
=P(A) x [1 - P(B)]
=P(A) - P(A).P(B)
=P(A) - P(AnB)
=P(AnB') shown

csleu

walrein_lim88,谢谢你的解答。你好厉害哦！请问你还在读书吗？你有msn吗？

walrein_lim88

walrein_lim88,谢谢你的解答。你好厉害哦！请问你还在读书吗？你有msn吗？
csleu 发表于 27-5-2010 11:08 AM

    等着IPTA消息着。。。。

50912cmea

1. Oxford Fajar Ace Ahead Vol 2 quick check 2.9 question no. 3 (a)
There might be typo error??? someone please help to check!!!
The question should be：(cos A + 2 cos 2A + cos 3A) / (cos A - 2 cos 2A + cos 3A) = - cot^2 (A/2)
2. Example 2.31 对不对？
3. Exam Practice 2 question no. 9 (b) please help to prove!!!
4. Quick check 2.13 question no. 5 why the answer is only 109 degree 28'???
Please help

csleu

walrein_lim88

1. Oxford Fajar Ace Ahead Vol 2 quick check 2.9 question no. 3 (a)
There might be typo error??? som ...
50912cmea 发表于 27-5-2010 11:41 AM

    1. 对，问题有问题。。。它的DENOMINATOR应该是 cos A - 2cos 2A + cos 3A
    2. 没有问题。。不明白??
    3. 这题：建议你把它画出来，相信你应该会看到的。
    4.  cosec A = cot A + (sqrt 2)
        1/sin A  = cos A/sin A  + (sqrt 2)
       (1 - cos A  -sqrt 2sin A)/sin A =0
       cos A + sqrt 2 sin A =1
       sqrt 3 cos (A - 54.74) = 1
       cos (A - 54.74 ) = 1/(Sqrt 3)
       A - 54.74 = 54.74, 305.26
                A =109.48, 370
  Since A < 360, A = 109.48

walrein_lim88

csleu 发表于 27-5-2010 11:46 AM

50912cmea

回复 291# walrein_lim88

Thanks for the advice and sorry to clarify again2. Example 2.31, should the answer be 15° ≤ x ≤ 165° or 195° ≤ x ≤ 345°?
3. Exam Practice 2 question no. 9 (b), i checked the model answer from the web site, two different tan (different angles) have been treated as same denominator???
4.  cosec A = cot A + (sqrt 2)
        1/sin A  = cos A/sin A  + (sqrt 2)
       (1 - cos A  -sqrt 2sin A)/sin A =0
       cos A + sqrt 2 sin A =1
       sqrt 3 cos (A - 54.74) = 1
       cos (A - 54.74 ) = 1/(Sqrt 3)
       A - 54.74 = 54.74, 305.26
                A =109.48, should be 360

walrein_lim88

回复  walrein_lim88

Thanks for the advice and sorry to clarify again2. Example 2.31, should the  ...
50912cmea 发表于 29-5-2010 11:12 PM

    哈哈。。我犯了怎么多错误：
    2. 我看到了，你的答案对。。EXAMPLE算错了。
    3.
    4. 对不起，我算错。。不过360 还是不能被接受。。。因为 cosec 360 or 1/sin 360 is undefined.
   

50912cmea

回复 294# walrein_lim88

你是难得糊涂，小小瑕疵，no harm， 没事没事第四题，峰回路转，我也看走眼lah

sim91

A four-digit number,in the range 000 to 999 inclusive,is formed.Find the probability thata)the number begins or ends with 0
b)the number contains exactly two non-zero digits
这题不会做啊 可以教教我嘛

walrein_lim88

A four-digit number,in the range 000 to 999 inclusive,is formed.Find the probability thata)the number begins or ends with 0
b)the number contains exactly two non-zero digits
sim91 发表于 10-6-2010 12:35 PM

a) Begins with 0 or end wif 0 = (1 x 10 x 10 )  +    begins wif 0 (include 0X0)
                                            (10 x 10 x 1 )         ends wif 0 (include 0X0)
                                            - (1 x 10 x 1 )        repetition (0X0) twice occurs, and hence (-)  away
                                          =180

b) two non-zero digit:
    = 1 x 9 x 9 (0 at 1st place) +
        9 x 1 x 9 (0 at 2nd place) +
        9 x 9 x 1 ( 0 at 3rd place)
   =243

tiewkj

请问下画boxplot的时候如果题目没有要求我们找outliers,我们需不需要找upper和lower boundaries?(Q1+1.5(Q3-Q1))?因为补习老师说题目没有要求的话我们去找就要被扣两分，学校老师就说不管怎样都要找，如果没有找就要被扣两分。到底要怎样？谁能帮帮我？

P/S:学校老师没有批改考卷，补习老师以前是学校老师，现在不知道还有没有定期update最新资讯。

walrein_lim88

请问下画boxplot的时候如果题目没有要求我们找outliers,我们需不需要找upper和lower boundaries?(Q1+1.5(Q3 ...
tiewkj 发表于 11-6-2010 10:04 PM

    学校老师就说不管怎样都要找，如果没有找就要被扣两分。<=我听到是这个。。。
    其实写多不扣分，写少就少分 。 <= exam theory ...

tiewkj

回复 299# walrein_lim88

我之前也是酱认为，不过补习老师又说中六和以前不同，所以我很乱咯。那就是说，不管怎样都要找咯？

walrein_lim88

回复  walrein_lim88

我之前也是酱认为，不过补习老师又说中六和以前不同，所以我很乱咯。那就是说，不 ...
tiewkj 发表于 12-6-2010 02:37 PM

    不管这样都要找～～