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The Maths Thread! |
50Cent
Joined: Nov 08, 2003
Posts: > 500
From: ...whatever psycho!!!
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oh noooooo. i just learnt that,  obviously hasnt sunk in yet!
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maddav
Joined: Dec 01, 2002
Posts: 356
From: Nottingham, UK
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That's alright, I'm confused as to how the book got the answer (as the answers are just in listed in the back, no explanation).
I'll just wait patiently for Kim!
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k4m!k4ze
Joined: Oct 02, 2004
Posts: > 500
From: CBE
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i got the answer as y=3, -1/3
Here's how -
eqns - x = 2y - 2
and x^2 = y^2 + 7
substitue value of x in eqn 1 in eqn 2,
(2y - 2)^2 = y^2 + 7
=> 4y^2 + 4 - 8y = y^2 + 7
=> 3y^2 - 8y - 3 = 0
So by splitting middle term technique,
prod = -9
Sum = -8
so -8y can be split as 9y - y
3y^2 + 9y - y -3 = 0
3y(y+3) - 1(y+3) = 0
(3y - 1) (y+3) = 0
so y=1/3 and y=-3
Simple 
This is the technique i was taught. Quite simple eh ?
@kimcheeboi - Man, if you had given those calculus and parabola sums a few years (3) back i woulda solved them but i forgot all those now.
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My precious - my K700
[ This Message was edited by: kllr_dude on 2004-10-28 18:43 ] |
k4m!k4ze
Joined: Oct 02, 2004
Posts: > 500
From: CBE
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@maddav - here's where you went wrong -
4y^2 -4y -4y +4 = y^2 +7
is 3y^2 - 8y - 3 = 0
and not 3y^2 - 8y -11 = 0 as you said. 
@50 cents - You really need tutoring buddy -
squaring x = 2y - 2
gives x^2 = 4y^2 + 4 - 8y
and not x^2=4y^2-2.
If at first you don't succeed, destroy all evidence of your attempt !! |
maddav
Joined: Dec 01, 2002
Posts: 356
From: Nottingham, UK
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That's it!
I realised my earlier mistake of putting in -11, instead of -3. I don't know how i did that one!
Thanks kllr_dude 
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k4m!k4ze
Joined: Oct 02, 2004
Posts: > 500
From: CBE
PM |
Man ! I MUST BE CRAZY !
I didnt even solve such sums in high school even though the teacher begged us to do so !  Of course we solved it once she threatened to call up our parents.
And now i'm sitting here solving them instead of studying for my upcoming exams and that too voluntarily.
Just wish there was somethin like this when i was in high school. Woulda studied better !
If at first you don't succeed, destroy all evidence of your attempt !! |
maddav
Joined: Dec 01, 2002
Posts: 356
From: Nottingham, UK
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It's always better with people you can ask
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50Cent
Joined: Nov 08, 2003
Posts: > 500
From: ...whatever psycho!!!
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Quote:
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On 2004-10-28 19:40:26, kllr_dude wrote:
@50 cents - You really need tutoring buddy -
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tell me about it
got a A* in maths tho
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maddav
Joined: Dec 01, 2002
Posts: 356
From: Nottingham, UK
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Well you beat me then, i got an A.
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k4m!k4ze
Joined: Oct 02, 2004
Posts: > 500
From: CBE
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I got an A+ too but that was in 10th standard (95 %)
I dont know much bout grades cuz over here we talk mainly in terms of percentage.
But i got a pitiful 75 % in my 12th ( i dont know the equivalent of 12th or 10th in US and other countries) .
If at first you don't succeed, destroy all evidence of your attempt !! |
50Cent
Joined: Nov 08, 2003
Posts: > 500
From: ...whatever psycho!!!
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we cant probably determine that via ur age. I'm 17 and took the exams earlier this year.
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k4m!k4ze
Joined: Oct 02, 2004
Posts: > 500
From: CBE
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I'm 20 and i'm gonna finish four years of college by June 2005. So that means i wrote the 12th exams when i was 16.
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[ This Message was edited by: kllr_dude on 2004-10-28 19:52 ] |
maddav
Joined: Dec 01, 2002
Posts: 356
From: Nottingham, UK
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Sounds similar to the GCSE's I took, in which i got an A, but in all fairness, grades on an exam, don't always translate, to good/bad overall competence in a subject.
Just my thoughts!
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50Cent
Joined: Nov 08, 2003
Posts: > 500
From: ...whatever psycho!!!
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as i have just proved cant even square terms
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50Cent
Joined: Nov 08, 2003
Posts: > 500
From: ...whatever psycho!!!
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y=2x + 1
y^2=2x^2 +x
how do i do this
Trusted Trader: 50Cent (+6, -0)
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Posted: 2004-10-28 19:22
