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5 Jan 2005, 21:56
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#1
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Aardvark is a funny word
Join Date: Sep 2002
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[Dunderhead] Maths question
Today's delightful AS Maths mock:
"Express √75 in the form (a + √b)/c, where a, b and c are integers."
Please, someone, a hand? It'd be staggeringly easy as (a√b)/c but that, alas, is not the question.
__________________
Efficiency, efficiency they say
Get to know the date and tell the time of day
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How the Beaujolais is raining
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5 Jan 2005, 22:22
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#2
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Ball
Join Date: Oct 2001
Posts: 4,410
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Re: [Dunderhead] Maths question
a=0
b=75
c=1
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5 Jan 2005, 22:24
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#3
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Aardvark is a funny word
Join Date: Sep 2002
Location: I'm No Nino Rota
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Re: [Dunderhead] Maths question
Quote:
Originally Posted by queball
a=0
b=75
c=1
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ah.
good grief, that's cheap
__________________
Efficiency, efficiency they say
Get to know the date and tell the time of day
As the crowds begin complaining
How the Beaujolais is raining
Down on darkened meetings on the Champs Élysées
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5 Jan 2005, 22:28
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#4
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Next goal wins!
Join Date: Sep 2000
Location: London
Posts: 5,406
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Re: [Dunderhead] Maths question
that doesnt really seem AS level to me...
the answer i mean, not the question.
__________________
bastard bastard bastard bastard
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5 Jan 2005, 22:56
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#5
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:alpha:
Join Date: May 2002
Location: London, UK
Posts: 7,871
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Re: [Dunderhead] Maths question
It's not the right answer, is it?
0 isn't an integer.
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"There is no I in team, but there are two in anal fisting"
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5 Jan 2005, 22:57
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#6
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The Twilight of the Gods
Join Date: Jan 2001
Posts: 23,481
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Re: [Dunderhead] Maths question
Quote:
Originally Posted by Tomkat
It's not the right answer, is it?
0 isn't an integer.
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Yes it is.
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5 Jan 2005, 23:03
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#7
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The Arson Specialist
Join Date: May 2002
Location: The Deep Shores of Hell
Posts: 524
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Re: [Dunderhead] Maths question
I do AS Maths and that is not a AS Maths question. You dont do edexcel do you?
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Quote:
Originally Posted by Dace
i like infernos avatar
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Please dont laugh at me. I'm not trying to be funny.
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5 Jan 2005, 23:14
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#8
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☆ ♥
Join Date: Jan 2003
Posts: 3,489
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Re: [Dunderhead] Maths question
I'm doing Further Maths
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5 Jan 2005, 23:17
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#9
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The Arson Specialist
Join Date: May 2002
Location: The Deep Shores of Hell
Posts: 524
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Re: [Dunderhead] Maths question
So am I. It sucks!
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Quote:
Originally Posted by Dace
i like infernos avatar
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Please dont laugh at me. I'm not trying to be funny.
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5 Jan 2005, 23:22
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#10
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Next goal wins!
Join Date: Sep 2000
Location: London
Posts: 5,406
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Re: [Dunderhead] Maths question
you fools!
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bastard bastard bastard bastard
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5 Jan 2005, 23:24
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#11
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The Arson Specialist
Join Date: May 2002
Location: The Deep Shores of Hell
Posts: 524
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Re: [Dunderhead] Maths question
An ignorant man is in eternal bliss!
__________________
Quote:
Originally Posted by Dace
i like infernos avatar
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Please dont laugh at me. I'm not trying to be funny.
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5 Jan 2005, 23:34
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#12
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☆ ♥
Join Date: Jan 2003
Posts: 3,489
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Re: [Dunderhead] Maths question
Quote:
Originally Posted by Inferno
So am I. It sucks!
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Aye. We've finished C1, C2, S1 & M1 - now that's left for the rest of the year is to study C3 & C4. C1, C2 & S1 are all easy - M1 is something I don't ****ing get. C3 has been fine so far - we started on the differentiation chapter which is piss-easy bar the quoitent rule will takes forever to work out - am getting used to how to derive to cot, cosec and sec - don't remember the exact methods but I'll learn the outcomes eventually. Moving onto the trig chapter & graphs chapters now - don't really understand the whole modulus crap and we were asked to look over some exam q's @ end of book - no-where in the book does it say anything about what g(x) is and yet there's a question on it - woo!
Also, in the last lesson, the teacher spent it teaching DeMoivre's theorem and spending the double lesson explaining imaginary no's in preperation for C4 or P4 or something. I missed the lesson before it so don't know where and why it came up
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5 Jan 2005, 23:40
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#13
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Love's Sweet Exile
Join Date: May 2001
Location: Living on a Stair (Now Sword-less)
Posts: 2,371
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Re: [Dunderhead] Maths question
g(x) is just a function of x, like f(x) but with a different letter.
I'm sure I knew that at GCSE...
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--SYMM--
Ba Ba Ti Ki Di Do
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5 Jan 2005, 23:46
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#14
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:alpha:
Join Date: May 2002
Location: London, UK
Posts: 7,871
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Re: [Dunderhead] Maths question
Quote:
Originally Posted by MrL_JaKiri
Yes it is.
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My mistake then. It's a long time since I did A-level Maths
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"There is no I in team, but there are two in anal fisting"
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5 Jan 2005, 23:50
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#15
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The Arson Specialist
Join Date: May 2002
Location: The Deep Shores of Hell
Posts: 524
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Re: [Dunderhead] Maths question
SYMM is right about the g(x).
But imaginary numbers suck. Some clever clog came up with the idea that you cant get √-1 so you replace it with i or j. j² is equal to -1 and that helps with solving certain equations and is vital in an engineer's work. Nothing much to it, just know what it is and how to solve it and you are sorted.
Someone answer Phang's question since we have totally derailed from his question/thread.
__________________
Quote:
Originally Posted by Dace
i like infernos avatar
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Please dont laugh at me. I'm not trying to be funny.
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6 Jan 2005, 02:31
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#16
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The Twilight of the Gods
Join Date: Jan 2001
Posts: 23,481
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Re: [Dunderhead] Maths question
Quote:
Originally Posted by Inferno
But imaginary numbers suck. Some clever clog came up with the idea that you cant get ?-1 so you replace it with i or j. j² is equal to -1 and that helps with solving certain equations and is vital in an engineer's work. Nothing much to it, just know what it is and how to solve it and you are sorted.
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Just i, actually. i and j are only used together in the context of unit vectors.
Imaginary numebrs are also a fine area of mathematics.
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6 Jan 2005, 02:50
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#17
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Jolt's best friend
Join Date: Feb 2003
Posts: 2,101
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Re: [Dunderhead] Maths question
i thought 'i' was the maths version and 'j' the engineering version?
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<Karmulian> subtle as a kick in the nuts as always
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6 Jan 2005, 03:00
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#18
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Ball
Join Date: Oct 2001
Posts: 4,410
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Re: [Dunderhead] Maths question
Quote:
Originally Posted by MrL_JaKiri
Just i, actually. i and j are only used together in the context of unit vectors.
Imaginary numebrs are also a fine area of mathematics.
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What mist said. Also, quarternions.
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6 Jan 2005, 10:16
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#19
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share the <3
Join Date: Aug 2001
Location: Location: Location:
Posts: 2,709
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Re: [Dunderhead] Maths question
Quote:
Originally Posted by mist
i thought 'i' was the maths version and 'j' the engineering version?
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it is (to avoid confusion with current), but like jakiri said when dealing with vectors you use i and j.
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Sophie is hotter than you
though ive gone off her now; the way Susanna Reid squirms around on sml is, however, awesome
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6 Jan 2005, 10:27
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#20
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☆ ♥
Join Date: Jan 2003
Posts: 3,489
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Re: [Dunderhead] Maths question
Good riddance.
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6 Jan 2005, 11:16
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#21
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J to the C to the A G E
Join Date: Sep 2000
Location: Scúnthorpe
Posts: 5,583
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Re: [Dunderhead] Maths question
M1 is really stupid and crap and I hate it
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6 Jan 2005, 11:35
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#22
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Wankoverable
Join Date: Apr 2002
Location: wherever I am
Posts: 726
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Re: [Dunderhead] Maths question
Hey guys I'm wondering over the original question too, I tried so hard and got so far. But in the end it didn't even matter! Anyone know how to solve it? please post solution ta
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Don't worry, life is too long.
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6 Jan 2005, 11:46
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#23
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Registered User
Join Date: Jun 2000
Posts: 8,476
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Re: [Dunderhead] Maths question
Quote:
Originally Posted by Flayer
Hey guys I'm wondering over the original question too, I tried so hard and got so far. But in the end it didn't even matter! Anyone know how to solve it? please post solution ta
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queball answered it in the 2nd post in this thread...
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6 Jan 2005, 11:47
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#24
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Wankoverable
Join Date: Apr 2002
Location: wherever I am
Posts: 726
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Re: [Dunderhead] Maths question
Quote:
Originally Posted by Nodrog
queball answered it in the 2nd post in this thread...
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Yes, but do other solutions exist? I think not!
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Don't worry, life is too long.
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6 Jan 2005, 11:56
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#25
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The Twilight of the Gods
Join Date: Jan 2001
Posts: 23,481
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Re: [Dunderhead] Maths question
Hmmm.
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6 Jan 2005, 12:56
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#26
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Registered User
Join Date: Oct 2000
Posts: 4,944
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Re: [Dunderhead] Maths question
16
3
2
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I find it kind of funny
I find it kind of sad
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6 Jan 2005, 12:59
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#27
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The Twilight of the Gods
Join Date: Jan 2001
Posts: 23,481
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Re: [Dunderhead] Maths question
Quote:
Originally Posted by Ragnarak
16
3
2
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SQRT 78.6?
To put it another way, I don't think that 8 is equal to 9 SQRT3 / 2
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6 Jan 2005, 12:59
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#28
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Registered User
Join Date: Oct 2000
Posts: 4,944
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Re: [Dunderhead] Maths question
Am i wrong? Cos i got that as soon as i typed in root 75 to my calculator and recognised that after the decimal was (root 3)/2 (which i guess they think is probably a number you should be able to recognise)
ps. i suck at maths
__________________
I find it kind of funny
I find it kind of sad
The dreams in which i'm dying
Are the best i've ever had
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6 Jan 2005, 13:01
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#29
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Registered User
Join Date: Oct 2000
Posts: 4,944
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Re: [Dunderhead] Maths question
Quote:
Originally Posted by MrL_JaKiri
SQRT 78.6?
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I didn't bother to check it properly I just recognised the root3/2 part and guessed at the rest.
Oh well, i suck at maths
__________________
I find it kind of funny
I find it kind of sad
The dreams in which i'm dying
Are the best i've ever had
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6 Jan 2005, 13:02
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#30
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The Twilight of the Gods
Join Date: Jan 2001
Posts: 23,481
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Re: [Dunderhead] Maths question
Quote:
Originally Posted by Ragnarak
Am i wrong? Cos i got that as soon as i typed in root 75 to my calculator and recognised that after the decimal was (root 3)/2 (which i guess they think is probably a number you should be able to recognise)
ps. i suck at maths
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SQRT 75 = SQRT 25 * SQRT 3 = 5 SQRT 3. You've accounted for 0.5 of the SQRT 3's.
It's also a good idea to 'test' the numbers you come up with.
Anyway, this is all pointless. It's fairly obvious that there's only one form of solution, where a = 0. c works for any natural number, you just have to multiply b by c^2 to get the ratio correct.
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6 Jan 2005, 13:39
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#31
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m00
Join Date: Jun 2001
Location: uk, Nottingham
Posts: 252
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Re: [Dunderhead] Maths question
Maths/Further maths AS is piss easy infact AS levels are piss easy.
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6 Jan 2005, 13:40
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#32
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The Twilight of the Gods
Join Date: Jan 2001
Posts: 23,481
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Re: [Dunderhead] Maths question
Quote:
Originally Posted by mist
i thought 'i' was the maths version and 'j' the engineering version?
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**** engineering!
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6 Jan 2005, 13:51
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#33
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Lord Denning
Join Date: Feb 2003
Location: City of London
Posts: 2,548
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Re: [Dunderhead] Maths question
I'm so glad after reading this thread that A-Level Further Maths is behind me. (Although P4 and P6 were quite fun.)
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Please bear in mind when reading the above post that I am always right.
Quote:
Originally Posted by Marilyn Manson
He was crowned in York Cathedral as 'Expert in the West' by Pope Urban III in 1186.
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6 Jan 2005, 13:59
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#34
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Made of Twigs
Join Date: Jun 2003
Posts: 5,459
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Re: [Dunderhead] Maths question
Quote:
Originally Posted by Proteus
(Although P4 and P6 were quite fun.)
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No they ****ing wern't.
Ragnarak - back me up on this.
P4, (P5) and P6 were bastards if you were a work shy individual like I.
Because one had never seen anything like the majority of stuff on there before (and thankfully not since, vectors floating in 3d my arse), it was rather difficult to do well without exerting any effort.
__________________
If I hadn't seen such riches, I could live with being poor - James
It's hard to be humble when you're as great as I am - Muhammad Ali
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6 Jan 2005, 14:15
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#35
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Registered User
Join Date: Oct 2000
Posts: 4,944
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Re: [Dunderhead] Maths question
Quote:
Originally Posted by Stew
No they ****ing wern't.
Ragnarak - back me up on this.
P4, (P5) and P6 were bastards if you were a work shy individual like I.
Because one had never seen anything like the majority of stuff on there before (and thankfully not since, vectors floating in 3d my arse), it was rather difficult to do well without exerting any effort.
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At the time they were hard to do unless you just 'got' it naturally. Looking back they were pretty simple but i don't know about fun.
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I find it kind of funny
I find it kind of sad
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6 Jan 2005, 15:13
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#36
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The Twilight of the Gods
Join Date: Jan 2001
Posts: 23,481
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Re: [Dunderhead] Maths question
P4 and P6 (at least on my board) were immensely trivial, relatively more so than P1, 2 or 3.
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6 Jan 2005, 15:22
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#37
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Wankoverable
Join Date: Apr 2002
Location: wherever I am
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Re: [Dunderhead] Maths question
I am waiting for someone to give proof that there is no solution with a != 0
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Don't worry, life is too long.
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6 Jan 2005, 15:34
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#38
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The Twilight of the Gods
Join Date: Jan 2001
Posts: 23,481
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Re: [Dunderhead] Maths question
Quote:
Originally Posted by Flayer
I am waiting for someone to give proof that there is no solution with a != 0
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If a =! 0, then b has to be a perfect square (75c^2 = a^2 + b + 2aSQRT b*), otherwise the LHS would be integral, and the RHS wouldn't.
If b is a perfect square, then you have 5 SQRT 3 = (Integer + integer) / integer, and root 3 is irrational.
*squaring, and rearranging
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6 Jan 2005, 15:43
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#39
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Next goal wins!
Join Date: Sep 2000
Location: London
Posts: 5,406
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Re: [Dunderhead] Maths question
Quote:
Originally Posted by MrL_JaKiri
If a =! 0, then b has to be a perfect square (75c^2 = a^2 + b + 2aSQRT b*), otherwise the LHS would be integral, and the RHS wouldn't.
If b is a perfect square, then you have 5 SQRT 3 = (Integer + integer) / integer, and root 3 is irrational.
*squaring, and rearranging
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i was about to say that
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bastard bastard bastard bastard
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6 Jan 2005, 17:49
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#40
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I dunno...
Join Date: Jun 2003
Location: manchester
Posts: 1,502
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Re: [Dunderhead] Maths question
Not too many English students on here, then?
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He shall drink naught but brine, for I'll not show him / Where the quick freshes are.
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6 Jan 2005, 18:02
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#41
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The Twilight of the Gods
Join Date: Jan 2001
Posts: 23,481
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Re: [Dunderhead] Maths question
Quote:
Originally Posted by Boogster
Not too many English students on here, then?
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All of the Arts students I know did maths to at least AS.
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6 Jan 2005, 18:28
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#42
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I dunno...
Join Date: Jun 2003
Location: manchester
Posts: 1,502
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Re: [Dunderhead] Maths question
Ergh. I did not.
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He shall drink naught but brine, for I'll not show him / Where the quick freshes are.
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6 Jan 2005, 18:41
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#43
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Aardvark is a funny word
Join Date: Sep 2002
Location: I'm No Nino Rota
Posts: 5,923
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Re: [Dunderhead] Maths question
Quote:
Originally Posted by MrL_JaKiri
All of the Arts students I know did maths to at least AS.
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yes, but isn't AS Maths pretty much a requirement at Cambridge?
__________________
Efficiency, efficiency they say
Get to know the date and tell the time of day
As the crowds begin complaining
How the Beaujolais is raining
Down on darkened meetings on the Champs Élysées
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6 Jan 2005, 19:11
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#44
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Rawr rawr
Join Date: Dec 2000
Location: Upside down
Posts: 5,300
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Re: [Dunderhead] Maths question
Quote:
Originally Posted by queball
a=0
b=75
c=1
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First thing that popped in my head too... I laughed out loud when I read your post.
__________________
"Yay"
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6 Jan 2005, 19:49
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#45
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Made of Twigs
Join Date: Jun 2003
Posts: 5,459
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Re: [Dunderhead] Maths question
Quote:
Originally Posted by Structural Integrity
I laughed out loud when I read your [queball's] post.
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Then you dear sir need to get yourself a life
__________________
If I hadn't seen such riches, I could live with being poor - James
It's hard to be humble when you're as great as I am - Muhammad Ali
So **** y'all, all of y'all; if y'all don't like me, blow me! - Dr. Dre
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6 Jan 2005, 20:20
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#46
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Rawr rawr
Join Date: Dec 2000
Location: Upside down
Posts: 5,300
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Re: [Dunderhead] Maths question
Quote:
Originally Posted by Stew
Then you dear sir need to get yourself a life
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I was waiting for someone to mention that. But I guess you're kind of right.
Still, it's an incredibly simple solution for a seemingly difficult question. I suspect this to be somesort of trick question.
__________________
"Yay"
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6 Jan 2005, 21:07
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#47
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I dunno...
Join Date: Jun 2003
Location: manchester
Posts: 1,502
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Re: [Dunderhead] Maths question
Quote:
Originally Posted by Phang
yes, but isn't AS Maths pretty much a requirement at Cambridge?
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Cambridge is the more science based of Oxbridge, or so I always thought.
__________________
He shall drink naught but brine, for I'll not show him / Where the quick freshes are.
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6 Jan 2005, 21:13
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#48
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Aardvark is a funny word
Join Date: Sep 2002
Location: I'm No Nino Rota
Posts: 5,923
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Re: [Dunderhead] Maths question
Quote:
Originally Posted by Boogster
Cambridge is the more science based of Oxbridge, or so I always thought.
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exactly my point.
__________________
Efficiency, efficiency they say
Get to know the date and tell the time of day
As the crowds begin complaining
How the Beaujolais is raining
Down on darkened meetings on the Champs Élysées
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6 Jan 2005, 23:01
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#49
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The Twilight of the Gods
Join Date: Jan 2001
Posts: 23,481
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Re: [Dunderhead] Maths question
Quote:
Originally Posted by Phang
yes, but isn't AS Maths pretty much a requirement at Cambridge?
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Nothing like a small sample size to guarantee overall trends!
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7 Jan 2005, 10:38
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#50
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Aardvark is a funny word
Join Date: Sep 2002
Location: I'm No Nino Rota
Posts: 5,923
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Re: [Dunderhead] Maths question
Quote:
Originally Posted by MrL_JaKiri
Nothing like a small sample size to guarantee overall trends!
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1)i know a dozen or so people (not online) who go to or went to cambridge and did maths at AS.
2)i know half a dozen more who tried to go to cambridge, had excellent but non-maths a-levels, but failed.
3)i don't know anyone who tried to get into cambridge with good grades including maths that didn't get in, barring a couple who instead went to oxford.
it's a small sample size, certainly, but there's certainly a trend there.
__________________
Efficiency, efficiency they say
Get to know the date and tell the time of day
As the crowds begin complaining
How the Beaujolais is raining
Down on darkened meetings on the Champs Élysées
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