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Author Topic: Math Doubt...  (Read 3013 times)

Offline I Jimmy I

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Math Doubt...
« on: May 03, 2009, 09:25:42 am »
Sup guyz...
Its been a long time since I practised for Maths and frankly I have a silly question....
My question is from Nov 2005, paper4, Question no. 2(c)

It says: translate triangle ABC by the vector (3,-9) and label this image A1,B1,C1
Now, the the points of triangle ABC are : (A=(2,2); B=(5,2); C=(5,4) )
What I want is how to calculate this sum step by step cuz I got an answer which is different from the Marking scheme...
Plz answer this question ASAP.
Thank You :D
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Offline astarmathsandphysics

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Re: Math Doubt...
« Reply #1 on: May 03, 2009, 09:37:51 am »
Quote from: I Jimmy I on May 03, 2009, 09:25:42 am
Sup guyz...
Its been a long time since I practised for Maths and frankly I have a silly question....
My question is from Nov 2005, paper4, Question no. 2(c)

It says: translate triangle ABC by the vector (3,-9) and label this image A1,B1,C1
Now, the the points of triangle ABC are : (A=(2,2); B=(5,2); C=(5,4) )
What I want is how to calculate this sum step by step cuz I got an answer which is different from the Marking scheme...
Plz answer this question ASAP.
Thank You :D
A goes to (2,2)+(3,-9)=(5,-7)=A1
B goes to (5,2)+(3,-9)=(8,-7)=B1
A goes to (5,4)+(3,-9)=(8,-5)=C1
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Offline I Jimmy I

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Re: Math Doubt...
« Reply #2 on: May 03, 2009, 09:41:15 am »
OMFG!!!!!!!!!!!!!!!


Its plus not multiplication...?
WTF is wrong with me these days...
*sigh*
Thank You m8 ur the best :D
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Offline forkasha

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Re: Math Doubt...
« Reply #3 on: May 06, 2009, 07:57:02 am »
HI
i have another math question it is in nov07/paper2
number 9 please
i would be greatful if u answered me as soon as possible
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Offline sweetsh

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Re: Math Doubt...
« Reply #4 on: May 06, 2009, 08:03:35 am »
Astar your help is needed.
forkasha's question is Nov07/P2
No.9)x2 + 4x – 8 can be written in the form (x + p)2 + q.
Find the values of p and q.
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Offline forkasha

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Re: Math Doubt...
« Reply #5 on: May 06, 2009, 08:07:03 am »
yes it is can u help me with it
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Offline yinyang

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Re: Math Doubt...
« Reply #6 on: May 06, 2009, 08:20:08 am »
first of all you need to know a technique

(a+b)2= a2+2*a*b+b2

by applying this technique, notice that the second value is a hint
so by looking at 4x you can make out the "a and b" values, which are a=x and b=2

so you have (x+2)2 when you expand it you have +4 instead of -8
so add a -12, the final form will become (x+2)2-12

p=2 and q=-12

« Last Edit: May 06, 2009, 08:46:47 am by yac_belga »
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Offline astarmathsandphysics

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Re: Math Doubt...
« Reply #7 on: May 06, 2009, 08:26:40 am »
P=4/2 q=-8-2^2=-12
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Offline forkasha

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Re: Math Doubt...
« Reply #8 on: May 06, 2009, 08:42:45 am »
aster can u explain more
 ;D
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Offline forkasha

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Re: Math Doubt...
« Reply #9 on: May 06, 2009, 08:52:46 am »
Quote from: yac_belga on May 06, 2009, 08:20:08 am
first of all you need to know a technique

(a+b)2= a2+2*a*b+b2

by applying this technique, notice that the second value is a hint
so by looking at 4x you can make out the "a and b" values, which are a=x and b=2

so you have (x+2)2 when you expand it you have a +4 instead of -8
so add a -12, the final form will become (x+2)2-12

p=2 and q=-12


first of all thanks for answering(yac_belga)+1 rep
but when i solved it i applied this rule but it didn't work
first i changed (X+p)2+q   to :
                                                         x2+2xp+p2+q
then wat

 
« Last Edit: May 06, 2009, 09:04:47 am by forkasha »
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Offline yinyang

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Re: Math Doubt...
« Reply #10 on: May 06, 2009, 09:10:54 am »
you shouldn't expand (x+p)2+q  it's just there as a guidance you should turn x2+4x-8 into that form.
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Offline forkasha

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Re: Math Doubt...
« Reply #11 on: May 06, 2009, 09:14:36 am »
how i still didn't get it >:(
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zara

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Re: Math Doubt...
« Reply #12 on: May 06, 2009, 09:15:39 am »
k..i kinda hv a logical explanation....
x2+2xp+p2+q
so,
2xp=4x
   p=4x/2x
   p=2
and for q,
x2+4x+22+q
so,
22+q=-8
q=-8-4
q=-12

is this f9??
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Offline forkasha

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Re: Math Doubt...
« Reply #13 on: May 06, 2009, 09:17:58 am »
how can i thank u zara u saved my life (lol)
really thanks(+1 Rep) :-*
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zara

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Re: Math Doubt...
« Reply #14 on: May 06, 2009, 09:19:28 am »
my pleasure to help others.... ;D
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