Math Is Fun Forum

Patrick

Real Member

Registered: 2006-02-24

Posts: 1,005

Equation of a Straight Line

Would just like to point out that in Denmark we use y=ax+b

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Ricky

Moderator

Registered: 2005-12-04

Posts: 3,791

Re: Equation of a Straight Line

In Virginia, we use:

Where p is a prime number.

Last edited by Ricky (2006-02-28 09:05:17)

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"In the real world, this would be a problem.  But in mathematics, we can just define a place where this problem doesn't exist.  So we'll go ahead and do that now..."

MathsIsFun

Administrator

Registered: 2005-01-21

Posts: 7,713

Re: Equation of a Straight Line

Ha ha!

Tak for det, Patrick!

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"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

krassi_holmz

Real Member

Registered: 2005-12-02

Posts: 1,905

Re: Equation of a Straight Line

Cool, ricky where did you get this?

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Ricky

Moderator

Registered: 2005-12-04

Posts: 3,791

Re: Equation of a Straight Line

I made it.  Just simpily and you should get:

y/(ab) = x/b + 1/a, which of course is y = ax + b

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"In the real world, this would be a problem.  But in mathematics, we can just define a place where this problem doesn't exist.  So we'll go ahead and do that now..."

Patrick

Real Member

Registered: 2006-02-24

Posts: 1,005

Re: Equation of a Straight Line

hehe, ricky - The reason I wrote this, was because of the request at the bottom of this page http://www.mathsisfun.com/equation_of_line.html

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Ricky

Moderator

Registered: 2005-12-04

Posts: 3,791

Re: Equation of a Straight Line

Ah, ok, didn't know about that Patrick.

Well Mathisfun?  Aren't you going to put mine on that page as well?

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"In the real world, this would be a problem.  But in mathematics, we can just define a place where this problem doesn't exist.  So we'll go ahead and do that now..."

krassi_holmz

Real Member

Registered: 2005-12-02

Posts: 1,905

Re: Equation of a Straight Line

Ya, now when i"m looking this MONSTER equation it looks loke very simple.
Pretty good example how BEAUTIFUL maths can be.

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MathsIsFun

Administrator

Registered: 2005-01-21

Posts: 7,713

Re: Equation of a Straight Line

Well Mathisfun?  Aren't you going to put mine on that page as well?

Do you think it will fit?

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"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

krassi_holmz

Real Member

Registered: 2005-12-02

Posts: 1,905

Re: Equation of a Straight Line

If it don't you can simplify it....
A little...
(You can call this "Ricky's approach")

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nikconsult

Member

Registered: 2006-08-04

Posts: 48

Re: Equation of a Straight Line

In Malaysia we use y=mx+c

Zhylliolom

Real Member

Registered: 2005-09-05

Posts: 412

Re: Equation of a Straight Line

I've never heard of any of the equations in this thread. In my studies I have always used

where ζ is Riemann's zeta function, Γ(x) is the gamma function, ∇ is the del operator, L[sup]-1[/sup] denotes the inverse Laplace transform, T[sub]n[/sub] is the nth Chebyshev polynomial of the first kind, C is a simple closed curve bounding a region having z = a as an interior point, σ[sub]0[/sub][sup]m[/sup] is a simplex of an oriented simplicial complex and [σ[sup]m[/sup], σ[sup]m - 1[/sup]] is an incidence number, S is a compact, orientable, differentiable k-dimensional manifold with boundary in E[sup]n[/sup] and ω is a (k - 1)-form in E[sup]n[/sup], defined, and C[sup]1[/sup] at all points of S, and η(x) is Dirichlet's eta function.

(Sorry for stealing your joke, Ricky. )

Last edited by Zhylliolom (2006-08-06 14:11:03)

MathsIsFun

Administrator

Registered: 2005-01-21

Posts: 7,713

Re: Equation of a Straight Line

Ha! That's only the simplified version!

nikconsult: updated page, mentioned Malaysia: Equation of a Straight Line

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"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

Ricky

Moderator

Registered: 2005-12-04

Posts: 3,791

Re: Equation of a Straight Line

(Sorry for stealing your joke, Ricky. )

That should read: "Sorry for taking your joke too far."

Now your going to force me to go through and check the entire thing.  And did I see a surface integral in there?  I had a calc professor who said, "You should only think one thing whenever you see a surface integral and that's, 'AHHHHH!!!!'"

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"In the real world, this would be a problem.  But in mathematics, we can just define a place where this problem doesn't exist.  So we'll go ahead and do that now..."

Zhylliolom

Real Member

Registered: 2005-09-05

Posts: 412

Re: Equation of a Straight Line

Making sure everything checks out would be a good exercise. After solving it, you'll realize that I made it rather simple... I should have made things crazier. Here are some things you can look into if you really want to see how it simplifies and get stuck: Elliptic integrals, obscure trigonometric identities, the Bromwich integral, obscure(and maybe somewhat non-obscure) infinite sums and products, definitions of obscure constants, contour integrals, simplicial homology theory, differential geometry, and integration of differential forms, just to name a few topics.

luca-deltodesco

Member

Registered: 2006-05-05

Posts: 1,470

Re: Equation of a Straight Line

in england, we tend to use y = mx + c

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Ricky

Moderator

Registered: 2005-12-04

Posts: 3,791

Re: Equation of a Straight Line

is C², right Zylliolom?

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"In the real world, this would be a problem.  But in mathematics, we can just define a place where this problem doesn't exist.  So we'll go ahead and do that now..."

Ricky

Moderator

Registered: 2005-12-04

Posts: 3,791

Re: Equation of a Straight Line

Isn't that supposed to be:

No?  Assumming it is, I got:

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"In the real world, this would be a problem.  But in mathematics, we can just define a place where this problem doesn't exist.  So we'll go ahead and do that now..."

Zhylliolom

Real Member

Registered: 2005-09-05

Posts: 412

Re: Equation of a Straight Line

No, A is an arbitrary vector. Just think about what the divergence of the curl is. I posted the formula for it in the Vector Formulas thread, but it should only take a moment to calculate it yourself.

Oh man, it's not letting me simply post "curl" again... and you're correct on the integral, I'll fix that typo right now.

Ricky

Moderator

Registered: 2005-12-04

Posts: 3,791

Re: Equation of a Straight Line

My book has that the divergence of a cur1 for any C^2 vector field F is 0... are you saying that C^2 is not needed?

And I got the same error when using cur1 as you did, hence the 1.

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"In the real world, this would be a problem.  But in mathematics, we can just define a place where this problem doesn't exist.  So we'll go ahead and do that now..."

Zhylliolom

Real Member

Registered: 2005-09-05

Posts: 412

Re: Equation of a Straight Line

That's good so far.

Ricky

Moderator

Registered: 2005-12-04

Posts: 3,791

Re: Equation of a Straight Line

If anyone wants to jump in here and help me out (besides Zhylliolom), feel free.

Of course, correct me if you see any mistakes.

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"In the real world, this would be a problem.  But in mathematics, we can just define a place where this problem doesn't exist.  So we'll go ahead and do that now..."

Zhylliolom

Real Member

Registered: 2005-09-05

Posts: 412

Re: Equation of a Straight Line

Wow, I don't know why I thought you meant C[sup]2[/sup] (as in some quantity or some vector) instead of C[sup]2[/sup].

Ricky

Moderator

Registered: 2005-12-04

Posts: 3,791

Re: Equation of a Straight Line

Cool integral.  Is there a special name for it?

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"In the real world, this would be a problem.  But in mathematics, we can just define a place where this problem doesn't exist.  So we'll go ahead and do that now..."

Zhylliolom

Real Member

Registered: 2005-09-05

Posts: 412

Re: Equation of a Straight Line

It's a special case of the polylogarithm known as the dilogarithm, this specific case is -Li[sub]2[/sub](1). Note that Li[sub]s[/sub](1) = ζ(s).

Last edited by Zhylliolom (2006-08-06 15:08:59)