>
New Topic
>
Reply<
Esato Forum Index
>
General discussions >
Non mobile discussion
> The Maths Thread!
Bookmark topic
oh noooooo. i just learnt that,
obviously hasnt sunk in yet!
--
Posted: 2004-10-28 19:22:23
Edit :
Quote
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!
--
Posted: 2004-10-28 19:23:51
Edit :
Quote
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.
_________________
My precious - my K700
[ This Message was edited by: kllr_dude on 2004-10-28 18:43 ]
--
Posted: 2004-10-28 19:34:19
Edit :
Quote
@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.
--
Posted: 2004-10-28 19:40:26
Edit :
Quote
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
--
Posted: 2004-10-28 19:43:17
Edit :
Quote
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 !
--
Posted: 2004-10-28 19:48:52
Edit :
Quote
It's always better with people you can ask
--
Posted: 2004-10-28 20:21:16
Edit :
Quote
Quote:
On 2004-10-28 19:40:26, kllr_dude wrote:
@50 cents - You really need tutoring buddy -
tell me about it
got a A* in maths tho
--
Posted: 2004-10-28 20:26:56
Edit :
Quote
Well you beat me then, i got an A.
--
Posted: 2004-10-28 20:33:47
Edit :
Quote
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) .
--
Posted: 2004-10-28 20:40:36
Edit :
Quote
New Topic
Reply
