# The Flat Earth Society

## Other Discussion Boards => Technology, Science & Alt Science => Topic started by: three-dimensional-world on June 02, 2011, 12:45:44 PM

Title: Math questions?
Post by: three-dimensional-world on June 02, 2011, 12:45:44 PM
Got any math questions you've wanted answers to but too afraid to ask? ILL TRY TO ANSWER THEM (unless someone else does it better first).  8)

(I make this thread for you because of the interest in math here)

Title: Re: Math questions?
Post by: Trekky0623 on June 02, 2011, 03:43:19 PM
Does P = NP?
Title: Re: Math questions?
Post by: Vindictus on June 02, 2011, 04:53:59 PM
Why can't I divide by zero?
Title: Re: Math questions?
Post by: Harutsedo on June 02, 2011, 04:57:32 PM
Does P = NP?

Think carefully, 3DW. We have \$1,000,000 riding on this.
Title: Re: Math questions?
Post by: three-dimensional-world on June 02, 2011, 05:40:43 PM
Does P = NP?

Obviously P is not equal to NP, sorry if you wanted proof... I can't prove it.

Why can't I divide by zero?

Normally you can't divide by zero because multiplication by zero wouldn't give back the original (it would give zero instead), of course there are situations where you can too.

-------

im going to bed will answer more questions tommorow.
Title: Re: Math questions?
Post by: Particle Person on June 02, 2011, 11:43:36 PM
does e?
Title: Re: Math questions?
Post by: three-dimensional-world on June 03, 2011, 02:40:56 AM
does e?

does e what??
Title: Re: Math questions?
Post by: Hazbollah on June 03, 2011, 05:13:19 AM
Say you have 1 divided by 0, I think it would give 1 because you haven't divided it by anything.
Title: Re: Math questions?
Post by: Hessy on June 03, 2011, 05:26:08 AM
Exact value of Pi.  No rounding please.
Title: Re: Math questions?
Post by: Hazbollah on June 03, 2011, 08:07:24 AM
Exact value of Pi.  No rounding please.
At my local chippy, ?3.10. You may have misspelt pie.
Title: Re: Math questions?
Post by: three-dimensional-world on June 03, 2011, 08:35:13 AM
Say you have 1 divided by 0, I think it would give 1 because you haven't divided it by anything.

hahaha

Exact value of Pi.  No rounding please.

pi is what mathematicians call a real number. This is defined as an infinite sequence of fractions which "gets closer and closer" to some limit. One way of writing out these sequences is using digits e.g. 3.141592653589... corresponds to the sequence (3,31/10,314/100,31415/100,...) but the ...'s are cheating: every ... should be able to be replaced with a method for continuing it indefinitely. The solution is to write a formula for the sequence of fractions: Here is one: f(0) = 0; f(n+1) = f(n) + (4(-1)^n)/(2n+1)

So f(1) = 0 + 4/1 = 4; f(2) = 4 - 4/3; f(3) = 4 - 4/3 + 4/5; f(4) = 4 - 4/3 + 4/5 - 4/7; f(5) = 1052/315; f(6) = 10312/3465.

so pi = (f(n))_n = (4,8/3,52/15,304/105,1052/315,10312/3465,...)

Title: Re: Math questions?
Post by: Trekky0623 on June 03, 2011, 10:21:56 AM
pi is what mathematicians call a real number.

I think you mean irrational. Of course it's real.
Title: Re: Math questions?
Post by: Roundy the Truthinessist on June 03, 2011, 04:42:32 PM
Is the real part of any non-trivial zero in the Riemann zeta function 1/2?
Title: Re: Math questions?
Post by: Crustinator on June 03, 2011, 04:47:33 PM
pi is what mathematicians call a real number.

I think you mean irrational. Of course it's real.

Title: Re: Math questions?
Post by: three-dimensional-world on June 03, 2011, 05:37:15 PM
Is the real part of any non-trivial zero in the Riemann zeta function 1/2?

:'( :'( :'( :'(

what the heck sort of answer did you want?
Title: Re: Math questions?
Post by: Tausami on June 03, 2011, 08:23:05 PM
Can you give me a proof for the segment addition postulate? It's gonna be on my test.
Title: Re: Math questions?
Post by: Roundy the Truthinessist on June 03, 2011, 08:46:59 PM
Is the real part of any non-trivial zero in the Riemann zeta function 1/2?

:'( :'( :'( :'(

what the heck sort of answer did you want?

THE CORRECT ONE!  I expect a proof.
Title: Re: Math questions?
Post by: Hazbollah on June 04, 2011, 01:34:50 AM
Say you have 1 divided by 0, I think it would give 1 because you haven't divided it by anything.

hahaha

What? I think we can safely say that zero means nothing. I am not holding an apple, I have zero apples. Zero denotes non-existence, as there is nothing there. Thus, you are dividing it by nothing, which is another way of saying you are not dividing it by anything.
Title: Re: Math questions?
Post by: Parsifal on June 04, 2011, 02:51:16 AM
What? I think we can safely say that zero means nothing. I am not holding an apple, I have zero apples. Zero denotes non-existence, as there is nothing there. Thus, you are dividing it by nothing, which is another way of saying you are not dividing it by anything.

By that logic, multiplying 1 by 0 also gives you 1, because you have not multiplied it by anything.

For a more direct rebuttal, consider what division means. 8 divided by 5 means "8 divided into 5 equal parts" -- each part would be 1.6 in magnitude. Now consider the meaning of 1 divided by 0; if you divide a single unit of something -- say, a brick -- into exactly zero parts, how many bricks do you have in each part? It isn't 1, because zero parts of one brick each nets you zero bricks.
Title: Re: Math questions?
Post by: three-dimensional-world on June 04, 2011, 06:13:38 AM
Can you give me a proof for the segment addition postulate? It's gonna be on my test.

Title: Re: Math questions?
Post by: Harutsedo on June 04, 2011, 10:40:29 AM
Is the real part of any non-trivial zero in the Riemann zeta function 1/2?

Yes. All of them, in fact. I would write down the proof, but it is too large to fit in the margins.
Title: Re: Math questions?
Post by: Roundy the Truthinessist on June 04, 2011, 10:41:14 AM
Is the real part of any non-trivial zero in the Riemann zeta function 1/2?

Yes. All of them, in fact. I would write down the proof, but it is too large to fit in the margins.

Oh, how conveeeeeenient.
Title: Re: Math questions?
Post by: optimisticcynic on June 13, 2011, 05:24:59 PM
ooo. I have a question actually... so I have been trying to come up with a "nice" equation that describes the electric field inside the plane of a ring... my integrals keep getting reaaaaally ugly and I was wondering if you can come up with a nice integral for it...
Title: Re: Math questions?
Post by: PizzaPlanet on June 13, 2011, 06:17:23 PM
4+4/4=?
Title: Re: Math questions?
Post by: Parsifal on June 13, 2011, 10:20:07 PM
4+4/4=?

2, obviously.
Title: Re: Math questions?
Post by: Harutsedo on June 13, 2011, 10:36:20 PM
4+4/4=?

2, obviously.

It's funny because you knowingly gave the wrong answer.
(http://profile.ak.fbcdn.net/hprofile-ak-snc4/41800_132964640069789_7386_n.jpg)
Title: Re: Math questions?
Post by: PizzaPlanet on June 14, 2011, 02:05:21 AM
Prove that the derivative of e^x is e^x.
Title: Re: Math questions?
Post by: Trekky0623 on June 14, 2011, 02:29:35 AM
4+4/4=?

2, obviously.

It's funny because you knowingly gave the wrong answer.
(http://profile.ak.fbcdn.net/hprofile-ak-snc4/41800_132964640069789_7386_n.jpg)

It's funny because nobody writes equations that way. Math is a language, and writing 4+4/4 is just poor wording on the writer's part because it is ambiguous. Now, if we follow the order of operations to the letter, yes, we'll get five. However, real mathematicians write it like this:

(http://euclid.hamline.edu/~arundquist/latex/showequation.php?eqn_id=182871)

OR

(http://euclid.hamline.edu/~arundquist/latex/showequation.php?eqn_id=182872)
Title: Re: Math questions?
Post by: Particle Person on June 14, 2011, 02:33:42 AM
4+4/4=?

2, obviously.

It's funny because you knowingly gave the wrong answer.
(http://profile.ak.fbcdn.net/hprofile-ak-snc4/41800_132964640069789_7386_n.jpg)

It's funny because nobody writes equations that way. Math is a language, and writing 4+4/4 is just poor wording on the writer's part because it is ambiguous. Now, if we follow the order of operations to the letter, yes, we'll get five. However, real mathematicians write it like this:

(http://euclid.hamline.edu/~arundquist/latex/showequation.php?eqn_id=182871)

OR

(http://euclid.hamline.edu/~arundquist/latex/showequation.php?eqn_id=182872)

It isn't ambiguous at all if the reader is at all familiar with the order of operations.
Title: Re: Math questions?
Post by: Trekky0623 on June 14, 2011, 03:54:18 AM
Is the real part of any non-trivial zero in the Riemann zeta function 1/2?

Yes. All of them, in fact. I would write down the proof, but it is too large to fit in the margins.

Fermat: the greatest troll in the history of mathematics.
Title: Re: Math questions?
Post by: Harutsedo on June 14, 2011, 07:53:22 AM
Prove that the derivative of e^x is e^x.

dx[ln(x)] = 1/x
dx[ln(e^x)] = dx[e^x]/e^x = dx[ x ] =1
For a fraction to be equal to one, both the numerator and denominator must be the same. Therefore, dx[e^x] = e^x

Man, e is awesome.
Title: Re: Math questions?
Post by: hoppy on June 14, 2011, 03:54:03 PM
What is 33+ 17?         ???
Title: Re: Math questions?
Post by: Thork on June 14, 2011, 05:45:08 PM
ooo. I have a question actually... so I have been trying to come up with a "nice" equation that describes the electric field inside the plane of a ring... my integrals keep getting reaaaaally ugly and I was wondering if you can come up with a nice integral for it...
http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/curloo.html#c1
Title: Re: Math questions?
Post by: optimisticcynic on June 14, 2011, 06:31:27 PM
ooo. I have a question actually... so I have been trying to come up with a "nice" equation that describes the electric field inside the plane of a ring... my integrals keep getting reaaaaally ugly and I was wondering if you can come up with a nice integral for it...
http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/curloo.html#c1
'thanks but that is the magnetic field at the center of a current loop. I was looking for the electric field as a function as how far we are from the center of the loop while still being in the plane.
Title: Re: Math questions?
Post by: Tausami on June 14, 2011, 06:51:43 PM
Someone tell me how thick the ice wall would have to be to hold in the world's oceans. I did it myself, but there's a lot of room for error and I want to be double checked. I came up with about 5/8 of a mile.
Title: Re: Math questions?
Post by: hoppy on June 15, 2011, 06:46:56 AM
What is 33+ 17?         ???
I'm still waiting. I thought this was just a troll thread.         >:(
Title: Re: Math questions?
Post by: parsec on June 15, 2011, 07:06:41 AM
Is the real part of any non-trivial zero in the Riemann zeta function 1/2?

Yes. All of them, in fact. I would write down the proof, but it is too large to fit in the margins.

That's the quote from Fermat's Small Theorem and not the Poincare and not suitable for the Riemann hypothesis.
Title: Re: Math questions?
Post by: PizzaPlanet on June 16, 2011, 08:41:54 AM
It's funny because nobody writes equations that way. Math is a language, and writing 4+4/4 is just poor wording on the writer's part because it is ambiguous.
lrn2linear notation

dx[ln(x)] = 1/x
Hold your horses. ln(x)dx = 1/x is a direct result of e^xdx = e^x. You can't prove the rule with itself.
Also, (for some obscure reason) you've used the chain rule without proving its validity. That's no proof at all. It's just restating what you were supposed to prove.
Title: Re: Math questions?
Post by: Harutsedo on June 16, 2011, 09:33:03 AM
Hold your horses. ln(x)dx = 1/x is a direct result of e^xdx = e^x. You can't prove the rule with itself.
Also, (for some obscure reason) you've used the chain rule without proving its validity. That's no proof at all. It's just restating what you were supposed to prove.

I'll prove ln(x)dx = 1/x, too then. And what do you mean 'without proving its validity'? The chain rule has already been proven to work with any function, hasn't it?

e = lim (x->Math.huge) [(1 + 1/x)^x], by definition
dx[ln(x)] = lim (Δx->0) [(ln(x + Δx) - ln(x)) / Δx], by definition
ln(x) - ln(y) = ln(x/y)
dx[ln(x)] = lim (Δx->0) [(ln((x + Δx) / x)) / Δx]
dx[ln(x)] = lim (Δx->0) [(1 / Δx)(ln(1 + Δx/x)]

Let u = x / Δx
As Δx approaches infinite, u approaches 0.
1 / Δx = u / x
Δx / x = 1 / u

dx[ln(x)] = lim (u->infinite) [(u / x)(ln(1 + 1/u)], by substitution
dx[ln(x)] = lim (u->infinite) [(1 / x)ln(1 + 1/u)^u]
1/x is a constant, so
dx[ln(x)] = (1 / x)lim (u->infinite) [ln(1 + 1/u)^u]
From the limit of the composition of functions,...
dx[ln(x)] = (1 / x)ln(lim (u->infinite) [(1 + 1/u)^u])
lim (u->infinite) [(1 + 1/u)^u] = e, by definition
dx[ln(x)] = (1 / x)ln(e)
dx[ln(x)] = 1 / x

:-\
Title: Re: Math questions?
Post by: jackie cox on June 16, 2011, 01:55:46 PM
when, where, and how were diagonal matrices first stacked and integrated into the same math model creating a math model capable of combining an infinite number of variables into a single math platform, or the beginning of emperical matrix ?
Title: Re: Math questions?
Post by: parsec on June 16, 2011, 02:36:29 PM
when, where, and how were diagonal matrices first stacked and integrated into the same math model creating a math model capable of combining an infinite number of variables into a single math platform, or the beginning of emperical matrix ?

wut
Title: Re: Math questions?
Post by: PizzaPlanet on June 16, 2011, 09:23:35 PM
e = lim (x->Math.huge) [(1 + 1/x)^x], by definition
This is not the definition of e. It's a derived equation. Derive it if you want to use it.
Title: Re: Math questions?
Post by: Parsifal on June 17, 2011, 05:34:11 AM
when, where, and how were diagonal matrices first stacked and integrated into the same math model creating a math model capable of combining an infinite number of variables into a single math platform, or the beginning of emperical matrix ?

This is a history question. Go and create a history questions thread if you want to post things like this.
Title: Re: Math questions?
Post by: Johannes on June 17, 2011, 12:24:50 PM
diagonalize my avatar