Form 3 maths (mc)

2007-11-10 1:32 am
想問1條mc..
http://xs221.xs.to/xs221/07455/maths.jpg <<上去睇題目
我想知邊個係answer..
點解果個係answer??
點解其他個3個唔係??
答晒我d 問題就比20分你!!
u can answer in both Chinese and English..

回答 (11)

2007-11-10 3:34 pm
✔ 最佳答案
D係答案

B對係因為:當J以90度轉到去K嘅時候,K嘅座標就會係J嘅座標調番轉。你可以試下,係真+!!例如:如果J嘅座標係(3,5)嘅話,咁K嘅座標就會係(-5,3),x軸係負數由於K位於負x軸嘅上面。而佢話K係(-y,x),其實入面嘅y同x只係一個代數,5係分別代表著y軸同x軸。如果要表示x軸同y軸,係括號入面嘅先後次序已經代表左啦!!如果5明嘅話,咁就睇番我上面嘅例子啦!!

A對係因為:由B對得知K嘅座標係(-y,x),用計距離嘅公式。就可以知道OJ=OR

C對係因為:當J垂直於x軸上而相交於M點時,兩者嘅x軸座標會係一樣。而M嘅y軸就會係0,所以M座標=(x,0)

D錯係因為:冇證據可以證明到角KON=角JOM,所以5能透過角KON+角JOM=90度而去搵角JOM=45度
參考: ME!!!!!!
2007-11-10 2:55 am
B瓜,我都唔係好清楚
參考: my sister
2007-11-10 2:39 am
我知道真正答案a~
答案係D
佢要你搵唔ARM的答案
而唔係ARM個D~
A , B , C 都係ARM的
不過正確答案係D
我保證一定ARM
參考: 自己
2007-11-10 2:03 am
The answer is B.
Because the correct coordinates of K is (-x,y)

∆OJM is equal to ∆OKN (RHS)
So, OJ = OK

and ∠JOM = ∠KON = a
So, a + a + 90度 = 180度
So, a = 45度
So, ∠JOM = 45度
Therefore, A and D is correct and they are not answer.

For answer C, the coordinates of M is (x,0)
Thus, answer C is correct and it is not an answer.
2007-11-10 1:56 am
answer係B
應該係(-x,y),而唔係(-y,x)
2007-11-10 1:55 am
b囉,,因為x要係頭(x,?)
唔係(?,x)
2007-11-10 1:54 am
b, because it should be like (x-axis, y-axis), but they turn it around in the other way..

so that why b was wrong..!!
參考: ME..!! WITH MY ENGLISH SKILL!!
2007-11-10 1:54 am
B
I am only try and i am only a s1.

2007-11-09 17:58:53 補充:
you can see that a is correct by you eyesd is easy to know that it is correct tooAnd there are B and C left so i think B is incorrect.

2007-11-09 17:59:55 補充:
應該係(-x,y),而唔係(-y,x)
參考: me
2007-11-10 1:54 am
我覺得b係答案
因為條題目係問邊個係incorrect
咁姐係有3個statement係岩啦
a係岩既因為你用眼睇都睇到啦
b係錯係因為coordinates係寫x axis跟住先寫y axis
同埋x axis個度應該係negative而唔係positive
而y axis個度應該係positive而唔係negative
c係岩既因為佢係寫x axis先,跟住先寫y axis
d係岩既因為x axis同y axis個到form左個right angle
所以angle JOM 係45度係岩既
答案a,c,d都係correct answer
咁b就係incorrect answer
2007-11-10 1:49 am
(a) is correct
it is because those triangle is a congrue triangle

2007-11-09 17:52:40 補充:
answer (b) must wrongas the coordiante的次序 is wrong already.
2007-11-10 1:49 am
answer is B

2007-11-09 17:51:10 補充:
use yr brain and think and you can understand

2007-11-10 09:57:00 補充:
many of you now can think, I am glad you know that the required ans. is the &quot;incorrect one&quot;, not the &quot;correct ones&quot;, most of them can get the reason why the ans. should be &quot;B&quot;, you guys are excellent. haha :)


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