Math Is Fun Forum
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#51 2015-05-06 05:37:57
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: 21 Questions from Amrita
Last 2 lines of the proof.
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
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#52 2015-05-06 11:46:53
Re: 21 Questions from Amrita
Nothing fishy there
'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.
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#53 2015-05-06 12:30:46
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: 21 Questions from Amrita
You understand differences?
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
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#54 2015-05-06 19:45:56
Re: 21 Questions from Amrita
2x?
I do not know what is wrong but please enlighten me
'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.
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#55 2015-05-07 03:35:10
- Bob
- Administrator
- Registered: 2010-06-20
- Posts: 10,643
Re: 21 Questions from Amrita
You need to convince me that they are the only roots
Doesn't post 10 show this?
Bob
Children are not defined by school ...........The Fonz
You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you! …………….Bob 
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#56 2015-05-07 09:31:58
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: 21 Questions from Amrita
I do not know what is wrong but please enlighten me
There is nothing wrong, I was asking if you have seen or used the difference calculus before.
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
Offline
#57 2015-05-07 11:52:34
Re: 21 Questions from Amrita
I haven't used it.
@bob: I do not get it.
'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.
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#58 2015-05-07 12:28:12
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: 21 Questions from Amrita
If a quadratic has roots of a and b, it means that (x-a) and (x-b) are factors of that quadratic. Conversely, if you have the factors ( x - a ) and ( x - b ) then c can not be a root because ( x - c ) is not a factor unless c = a or c = b.
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
Offline
#59 2015-05-07 12:29:59
Re: 21 Questions from Amrita
So, I will post a new question
'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.
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#60 2015-05-07 12:37:55
Re: 21 Questions from Amrita
3) If the p-th, q-th, r-th, s-th terms of an Arithmetic progression are in Geometric Progression, show that (p-q), (q-r), (r-s) are in Geometric Progression
Last edited by Agnishom (2015-05-07 12:39:08)
'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.
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#61 2015-05-07 19:16:32
- Bob
- Administrator
- Registered: 2010-06-20
- Posts: 10,643
Re: 21 Questions from Amrita
hi Agnishom,
If you write
a + (p-1)d = r[a + (q-1)d] and two more similar, and then subtract you get
d[(p-1) - (q-1)] = rd[(q-1) - (r-1)] and so on.
All you need to do is simplify this.
Bob
Children are not defined by school ...........The Fonz
You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you! …………….Bob
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#62 2015-05-09 12:47:50
Re: 21 Questions from Amrita
Thanks, the last time I checked, it worked
'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.
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#63 2015-05-09 13:38:38
Re: 21 Questions from Amrita
AmritaR wrote:If
25(9x^2 + y^2) + 9z^2 - 15(5xy + yz + 3xz) = 0
Prove that x,y,z form an AP
Proof:
25(9x^2 + y^2) + 9z^2 - 15(5xy + yz + 3xz) = 0
or, 225 x^2 + 25 y^2 + 9 z^2 - 75 x y - 15 y z - 45 x z = 0
or, (225 x^2 + 25 y^2 + 9 z^2 - 75 x y - 15 y z - 45 x z) + (225 x^2 + 25 y^2 + 9 z^2 - 75 x y - 15 y z - 45 x z) = 0 [Multiplying both sides by 2]
or, (225 x^2 - 75 x y - 75 x y + 25 y^2) + (25 y^2 - 15 y z - 15 y z + 9 z^2) + (9 z^2 - 45 x z - 45 x z + 225 x^2) = 0 [Rearrangement]
or, (15 x - 5 y)^2 + (5 y - 3 z)^2 + (3 z - 15 x)^2 = 0 (A)
But, by the trivial inequality:
(15 x - 5 y)^2, (5 y - 3 z)^2, (3 z - 15 x)^2 >= 0 (B)
From (A) and (B):
(15 x - 5 y)^2, (5 y - 3 z)^2, (3 z - 15 x)^2 = 0
Solving, we get:
(x, y, z) = (x, 3x, 5x)
Hence: x, y, z are in Arithmetic Progression.
'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.
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#64 2015-05-09 14:33:52
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: 21 Questions from Amrita
You think that one is easier than mine?
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
Offline
#65 2015-05-09 18:54:25
Re: 21 Questions from Amrita
Easy to understand? Yes
'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.
Offline
#66 2015-05-09 20:42:59
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: 21 Questions from Amrita
Hmmm, I like mine better.
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
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#67 2015-05-09 23:53:36
Re: 21 Questions from Amrita
Why? It looks like gibberish
'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.
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#68 2015-05-10 07:26:47
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: 21 Questions from Amrita
Hmmm, looks can be deceiving.
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
Offline
#69 2015-05-10 11:45:35
Re: 21 Questions from Amrita
Yep, I use that bobbym quote all the time.
Alokananda and I were waiting in the bus stop.
Me: Isn't that the bus you were looking for?
Alokananda: It looks so.
Me: but wait, looks can be deceiving
'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.
Offline
#70 2015-05-10 15:47:21
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: 21 Questions from Amrita
Where were you going?
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
Offline
#71 2015-05-10 20:31:33
Re: 21 Questions from Amrita
Going home
'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.
Offline
#72 2015-05-10 21:23:27
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: 21 Questions from Amrita
Where were you coming from?
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
Offline
#73 2015-05-10 22:07:51
Re: 21 Questions from Amrita
The school
'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.
Offline
#74 2015-05-10 22:24:45
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: 21 Questions from Amrita
You wait for the bus together?
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
Offline
#75 2015-05-10 22:28:58
Re: 21 Questions from Amrita
yes.
'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.
Offline