Comments on: Vectors – Never In An E-Maths Question http://www.exampaper.com.sg/questions/a-maths/vectors-never-in-an-e-maths-question Sassy O Level Maths Tuition, Questions & Tips from Singapore's Favourite Private Tutor Sun, 05 Feb 2012 17:08:39 +0000 hourly 1 By: kiroii http://www.exampaper.com.sg/questions/a-maths/vectors-never-in-an-e-maths-question#comment-518 kiroii Sun, 29 Jul 2007 06:01:55 +0000 http://www.exampaper.com.sg/questions/a-maths/vectors-never-in-an-e-maths-question#comment-518 -___- nah priv sch oh unit vector.. i read it as column vector hahas? anyway if i may exonerate myself by sayin my understandin of vectors is rather questionable? LOL -___- nah priv sch oh unit vector.. i read it as column vector hahas? anyway if i may exonerate myself by sayin my understandin of vectors is rather questionable? LOL

]]> By: Miss Loi http://www.exampaper.com.sg/questions/a-maths/vectors-never-in-an-e-maths-question#comment-517 Miss Loi Sun, 29 Jul 2007 04:50:25 +0000 http://www.exampaper.com.sg/questions/a-maths/vectors-never-in-an-e-maths-question#comment-517 Are you currently in Sec 4? If so, quite surprising that vectors have not yet been taught at this stage. Wei wei wei ... you're getting more and more careless! <m>vec{OB} = vec{OA} - vec{BA}</m> = <m>(matrix{2}{1}{{-40} 75}) - (matrix{2}{1}{{-35} 63})</m> = <m>(matrix{2}{1}{{-5} 12})</m>! <strong class="highlight">UNIT VECTOR</strong> in the direction of <m>vec{OB} = 1/{sqrt{(-5)^2 +12^2}}(matrix{2}{1}{{-5} 12})</m> = <m>{1/13}(matrix{2}{1}{{-5} 12})</m> What did Miss Loi just said in the previous comment?! Grrr... Are you currently in Sec 4? If so, quite surprising that vectors have not yet been taught at this stage.

Wei wei wei ... you're getting more and more careless!

vec{OB} = vec{OA} - vec{BA}
= (matrix{2}{1}{{-40} 75}) - (matrix{2}{1}{{-35} 63})
= (matrix{2}{1}{{-5} 12})!

UNIT VECTOR in the direction of vec{OB} = 1/{sqrt{(-5)^2 +12^2}}(matrix{2}{1}{{-5} 12})
= {1/13}(matrix{2}{1}{{-5} 12})

What did Miss Loi just said in the previous comment?! Grrr...

]]> By: kiroii http://www.exampaper.com.sg/questions/a-maths/vectors-never-in-an-e-maths-question#comment-513 kiroii Sat, 28 Jul 2007 15:40:43 +0000 http://www.exampaper.com.sg/questions/a-maths/vectors-never-in-an-e-maths-question#comment-513 -___-" yes mdm? truth is my sch hasnt taught vectors yet so my understanding of it is rather questionable >.> anyway BA = OA - OB, OB = OA - BA OB = (-75) ( 12) -___-" yes mdm? truth is my sch hasnt taught vectors yet so my understanding of it is rather questionable >.>

anyway BA = OA - OB, OB = OA - BA
OB = (-75)
( 12)

]]> By: Miss Loi http://www.exampaper.com.sg/questions/a-maths/vectors-never-in-an-e-maths-question#comment-512 Miss Loi Sat, 28 Jul 2007 14:36:45 +0000 http://www.exampaper.com.sg/questions/a-maths/vectors-never-in-an-e-maths-question#comment-512 kiroii, the <strong class="highlight">opposite direction</strong> of <m>(matrix{2}{1}{8 {-15}})</m> is <m>(matrix{2}{1}{{-8} 15})</m>! So <m>vec{OA} = 85*{1/sqrt{8^2+(-15)^2}}(matrix{2}{1}{{-8} 15})</m> =<m>85*{1/17}(matrix{2}{1}{{-8} 15})</m> =<m>{5}(matrix{2}{1}{{-8} 15})</m> =<m>(matrix{2}{1}{{-40} 75})</m> So can you get <m>vec{OB}</m> from here? Don't forget to express the final answer in <em>unit vector</em> coz that's what the question asked for. Too many students have lost valuable marks here simple coz they didn't read the question properly. Don't anyhow 'flip' again! Know your directions well! kiroii, the opposite direction of (matrix{2}{1}{8 {-15}}) is (matrix{2}{1}{{-8} 15})!

So vec{OA} = 85*{1/sqrt{8^2+(-15)^2}}(matrix{2}{1}{{-8} 15})
=85*{1/17}(matrix{2}{1}{{-8} 15})
={5}(matrix{2}{1}{{-8} 15})
=(matrix{2}{1}{{-40} 75})

So can you get vec{OB} from here? Don't forget to express the final answer in unit vector coz that's what the question asked for. Too many students have lost valuable marks here simple coz they didn't read the question properly.

Don't anyhow 'flip' again! Know your directions well!

]]> By: kiroii http://www.exampaper.com.sg/questions/a-maths/vectors-never-in-an-e-maths-question#comment-508 kiroii Sat, 28 Jul 2007 03:29:24 +0000 http://www.exampaper.com.sg/questions/a-maths/vectors-never-in-an-e-maths-question#comment-508 since OA is in de opposite direction of ( 8 ) (-15) by flippin it to ( -15) ( 8 ) <span class="highlight">you 'flipped' wrongly here!</span> Then 1/(root square of [ (8^2) ( -15^2)] and we'll get 1/17. Now 1/17 x (-15) x 85 ( 8) OA = (-75) (40 ) from here OB is no biggie yes? ps: i dun see whats wrong wit my workings and sry abt de format cant seem to install the plugin ya recommanded since OA is in de opposite direction of
( 8 )
(-15)
by flippin it to ( -15)
( 8 ) you 'flipped' wrongly here!
Then 1/(root square of [ (8^2) ( -15^2)]
and we'll get 1/17. Now 1/17 x (-15) x 85
( 8)
OA = (-75)
(40 )
from here OB is no biggie yes? ps: i dun see whats wrong wit my workings and sry abt de format cant seem to install the plugin ya recommanded

]]> By: Miss Loi http://www.exampaper.com.sg/questions/a-maths/vectors-never-in-an-e-maths-question#comment-504 Miss Loi Fri, 27 Jul 2007 15:32:20 +0000 http://www.exampaper.com.sg/questions/a-maths/vectors-never-in-an-e-maths-question#comment-504 Sorry Kiroii, but your answer is far from the truth! You need to understand the concept of unit vectors well before you do this question. Miss Loi would like to look at your workings. Check out <a href="/miss-loi-the-tutor/revealing-equations-in-their-full-glory" rel="nofollow">this post</a> on how to display mathematical symbols in comments. Do check out the <a rel="external nofollow" href="http://www.xm1math.net/phpmathpublisher/doc/help.html" rel="nofollow">syntax guide</a> and <a rel="external nofollow" href="http://www.xm1math.net/phpmathpublisher/examples/online_demo.php" rel="nofollow">test out your equation</a> first before posting here! Sorry Kiroii, but your answer is far from the truth!

You need to understand the concept of unit vectors well before you do this question.

Miss Loi would like to look at your workings. Check out this post on how to display mathematical symbols in comments.

Do check out the syntax guide and test out your equation first before posting here!

]]> By: kiroii http://www.exampaper.com.sg/questions/a-maths/vectors-never-in-an-e-maths-question#comment-502 kiroii Fri, 27 Jul 2007 08:38:15 +0000 http://www.exampaper.com.sg/questions/a-maths/vectors-never-in-an-e-maths-question#comment-502 uh i dunno how to type de workings usin keyboard so i'll juz present de ans OA = (-75) (60) OB = (-110) (123 ) uh i dunno how to type de workings usin keyboard so i'll juz present de ans
OA = (-75)
(60)

OB = (-110)
(123 )

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