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Author Topic: maths doubts  (Read 3867 times)

Offline slvri

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Re: maths doubts
« Reply #15 on: October 31, 2009, 09:52:15 am »
Quote from: @d!_†oX!© on October 31, 2009, 09:45:10 am
dude!!!
fx-991 MS isn't allowed!!!!
really? i uesd 991ms in all my june 2009 papers :P :P :P
and thats good to hear adi.......so which papers have u already given?
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Offline Ghost Of Highbury

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Re: maths doubts
« Reply #16 on: October 31, 2009, 09:55:25 am »
Quote from: slvri on October 31, 2009, 09:52:15 am
really? i uesd 991ms in all my june 2009 papers :P :P :P
and thats good to hear adi.......so which papers have u already given?

only computer studies finished...as a subject..many more to go, :P
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Offline @d!_†oX!©

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Re: maths doubts
« Reply #17 on: October 31, 2009, 10:00:00 am »
dude for this question.....don't u just have to find the points of intersection of the both functions!!!!
cuz it says the equation is a simplified form of f(x)=g(x)
so the points where these both grphs meet is the answer.....it says "USE YOU GRAPH"
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Offline Ghost Of Highbury

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Re: maths doubts
« Reply #18 on: October 31, 2009, 10:01:47 am »
Quote from: cooldude on October 31, 2009, 09:57:06 am

okay i got the soft copy. it was on fep all the time. they usually give us a range, in this q 2.3-2.7 but i got 2.2. i usually find the exact ans by trial and improvement but that method is too time-consuming. so please temme another method to do it. this questions equation simplifies to (x^3)+3(x^2)-3x-27=0, i checked the ans by 991-ms, we get two complex roots and one real root, so if u hve a method to find the real root to about 3-4 sf i would appreciate it.

http://www.freeexampapers.us/IGCSE/Maths/CIE/2004%20Jun/0580_s04_qp_4.pdf (q2 (c) (ii))


there is another method..but its not dere for maths..v have it in add. math..

for this, first - u did some error in ur calci. u get correct values. no complex roots.

and yea..for the answer..u have to draw the curve very accurately..thats the only way ..wat i do is..

find the answer from my calculator..show the intersection in my graph..and write an answer which is close to the calci's answer and the graph answer..

@adi - i guess he already knows that!...he just said that he doesnt get an answer in the range provided in the ms ... hets it close to it!..CHILL MAN!..
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Offline slvri

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Re: maths doubts
« Reply #19 on: October 31, 2009, 10:03:21 am »
Quote from: A@di on October 31, 2009, 09:55:25 am
only computer studies finished...as a subject..many more to go, :P
was it easy or hard because the june 2009 one was &^&%^@ :P :P :P
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Offline Ghost Of Highbury

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Re: maths doubts
« Reply #20 on: October 31, 2009, 10:05:29 am »
Quote from: slvri on October 31, 2009, 10:03:21 am
was it easy or hard because the june 2009 one was &^&%^@ :P :P :P

lol..the june 2009 wasnt $#$%@ ... :P.. it was easy..but confronted lots of new questions,, :D
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Offline @d!_†oX!©

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Re: maths doubts
« Reply #21 on: October 31, 2009, 10:06:43 am »
ya cooldude!!!!!!
fuys pls get us a proof!!!!!!
we have to shut that tiny teacher of ours man!!!!!!!!!
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Offline Ghost Of Highbury

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Re: maths doubts
« Reply #22 on: October 31, 2009, 10:13:42 am »
Quote from: cooldude on October 31, 2009, 10:06:59 am

yeh dude but since we're not allowed those calcis so we cant get the exact roots. if u silvri or astar have any proof we are gonna stuff it into our maths teachers face on mon when we give fle.
any calcultors shud not be able to have these/or be capable of doing any of these

•   graphic display (tick)
•   data banks (tick)
•   dictionaries (tick)
•   language translators (tick)
•   retrieval or manipulation of text or formulae (tick)
•   QWERT keyboards (tick)
•   built-in symbolic algebra manipulations (tick)
•   symbolic differentiation or integration (not sure abt this, because i can do differentiation in this calci, wat is symbolic differentiation?)
•   capability of remote communication with other machines (tick) (ofcourse not lol :P)
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Offline astarmathsandphysics

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Re: maths doubts
« Reply #23 on: October 31, 2009, 10:15:26 am »
Quote from: cooldude on October 31, 2009, 09:57:06 am

okay i got the soft copy. it was on fep all the time. they usually give us a range, in this q 2.3-2.7 but i got 2.2. i usually find the exact ans by trial and improvement but that method is too time-consuming. so please temme another method to do it. this questions equation simplifies to (x^3)+3(x^2)-3x-27=0, i checked the ans by 991-ms, we get two complex roots and one real root, so if u hve a method to find the real root to about 3-4 sf i would appreciate it.

http://www.freeexampapers.us/IGCSE/Maths/CIE/2004%20Jun/0580_s04_qp_4.pdf (q2 (c) (ii))


use the Newton raphson method like this:
\fract {dy}{dx} =f'(x)=3x^2+6x-3
take x_0 =2.2

use x_{n+1} =x_n- \frac {f(x_n)}{f'(x_n)}

x_{1} =x_0- \frac {f(x_0)}{f'(x_0)} =2.2- \frac {2.2^3+3*2.2^2 -3*2.2 -27}{6*2.2^2+6*2.2-3)} =2.2 -\frac{-8.432}{24.72 =2.541
now put x_1 =2.541
x_2 =2.518
x_3 =2.5095
x_4 =2.5061
x_5 =2.5048
x_6 =2.5044
etc
« Last Edit: October 31, 2009, 11:21:27 am by astarmathsandphysics »
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Offline @d!_†oX!©

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Re: maths doubts
« Reply #24 on: October 31, 2009, 10:15:42 am »
Quote from: A@di on October 31, 2009, 10:13:42 am
any calcultors shud not be able to have these/or be capable of doing any of these

•   graphic display (tick)
•   data banks (tick)
•   dictionaries (tick)
•   language translators (tick)
•   retrieval or manipulation of text or formulae (tick)
•   QWERT keyboards (tick)
•   built-in symbolic algebra manipulations (tick)
•   symbolic differentiation or integration (not sure abt this, because i can do differentiation in this calci, wat is symbolic differentiation?)
•   capability of remote communication with other machines (tick) (ofcourse not lol :P)

built-in symbolic algebra manipulations (tick)
that is not a tick dude!!!!!!!!!
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Offline Ghost Of Highbury

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Re: maths doubts
« Reply #25 on: October 31, 2009, 10:21:19 am »
Quote from: @d!_†oX!© on October 31, 2009, 10:15:42 am
built-in symbolic algebra manipulations (tick)
that is not a tick dude!!!!!!!!!


ofcourse it is a tick

if i define Y = X + 2

and define X as 4

i wont get the value of Y as 6!!
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Offline @d!_†oX!©

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Re: maths doubts
« Reply #26 on: October 31, 2009, 10:27:14 am »
yeah cooldude...lets give it a shot!!!
nd ya this is from a file that sweetish posted rite???
i got that file too but didnt really pay attention on this.....
By the way aadi...wont the equations that we can solve on it count under this point????
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Offline Ghost Of Highbury

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Re: maths doubts
« Reply #27 on: October 31, 2009, 10:29:01 am »
Quote from: @d!_†oX!© on October 31, 2009, 10:27:14 am
yeah cooldude...lets give it a shot!!!
nd ya this is from a file that sweetish posted rite???
i got that file too but didnt really pay attention on this.....
By the way aadi...wont the equations that we can solve on it count under this point????

i dont think so ,,, By the way...dont argue now..just show it to her..its good for u...
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Offline @d!_†oX!©

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Re: maths doubts
« Reply #28 on: October 31, 2009, 10:31:15 am »
give me a link for this file plss aadi
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Offline Ghost Of Highbury

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Re: maths doubts
« Reply #29 on: October 31, 2009, 11:12:55 am »
Quote from: cooldude on October 31, 2009, 11:08:46 am
and also shudnt the value of f'(x0) while finding x1 be (3*(2.2^2)+(6*2.2)-3) since f'(x)=3(x^2)+6x-3 and not 6(x^2)+6x-3??

wen u differentiate 3x2 u get 6x
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