Omnimaga

General Discussion => Other Discussions => Math and Science => Topic started by: Deep Toaster on February 23, 2011, 11:54:01 pm

Title: Something you know
Post by: Deep Toaster on February 23, 2011, 11:54:01 pm
(http://www.mcglaun.com/euler.gif)

I'm still amazed every time I see it.
Title: Re: Something you know
Post by: Xeda112358 on February 23, 2011, 11:58:36 pm
I bet it has to do with taylor series for e^x and pi
Title: Re: Something you know
Post by: Deep Toaster on February 24, 2011, 12:00:39 am
Yep, it's all here: http://en.wikipedia.org/wiki/Euler's_formula#Proofs

But still it looks awesome.

http://xkcd.com/179/
Title: Re: Something you know
Post by: shmibs on February 24, 2011, 12:58:22 am
hey, that's my favourite equation!
it's not really worth anything, but it definitely looks pretty.
Title: Re: Something you know
Post by: SirCmpwn on February 24, 2011, 01:04:31 am
I'm a hard core atheist, but that's probably the most reasonable evidence of creationism I've seen.
Title: Re: Something you know
Post by: Builderboy on February 24, 2011, 01:27:20 am
That is, in my opinion, the most beautiful mathematical formula ever :) It uses the 5 most important numbers, uses 3 numbers from each large field of mathematics (i for imaginary, e for logarithmic, and pi for trigonometry) and it uses the 3 main mathematical operations (addition, multiplication, exponentiation)
Title: Re: Something you know
Post by: ralphdspam on February 24, 2011, 01:41:35 am
 O.O  :w00t:
Absolutely amazing.
Title: Re: Something you know
Post by: Xeda112358 on February 24, 2011, 03:12:36 am
And it is a very useful equation, too! I ♥ it.
Title: Re: Something you know
Post by: AngelFish on February 24, 2011, 03:32:31 am
That is, in my opinion, the most beautiful mathematical formula ever :) It uses the 5 most important numbers, uses 3 numbers from each large field of mathematics (i for imaginary, e for logarithmic, and pi for trigonometry) and it uses the 3 main mathematical operations (addition, multiplication, exponentiation)

Personally, I'm a fan of this guy:

http://farm5.static.flickr.com/4120/4816933933_ccdc87cf0a_b.jpg (http://farm5.static.flickr.com/4120/4816933933_ccdc87cf0a_b.jpg)
Title: Re: Something you know
Post by: Deep Toaster on February 24, 2011, 09:19:30 am
And it is a very useful equation, too! I ♥ it.

How do you use it?

That is, in my opinion, the most beautiful mathematical formula ever :) It uses the 5 most important numbers, uses 3 numbers from each large field of mathematics (i for imaginary, e for logarithmic, and pi for trigonometry) and it uses the 3 main mathematical operations (addition, multiplication, exponentiation)

Not to mention it's even set equal to zero. And you forgot to mention that the other two numbers (1 and 0) are pretty important in math two. Both the identity numbers at once :)
Title: Re: Something you know
Post by: Xeda112358 on February 24, 2011, 11:52:53 am
Think about how you would do something like raising something to an imaginary power :D You can set up ratios and stuff and do more stuff and stuff. Also, e^(ix)=cos(x)+isin(x), so 3^i would be cos(ln(3))+isin(ln(3))

EDIT: so you can say with that the idea that e^(i2pi)-1=0 (that is i times 2 times pi)
Title: Re: Something you know
Post by: ruler501 on February 24, 2011, 05:27:06 pm
Think about how you would do something like raising something to an imaginary power :D You can set up ratios and stuff and do more stuff and stuff. Also, e^(ix)=cos(x)+isin(x), so 3^i would be cos(ln(3))+isin(ln(3))

EDIT: so you can say with that the idea that e^(i2pi)-1=0 (that is i times 2 times pi)
so what you are saying is that e^i*n*pi)-1=0 where n is any natural number(possibly negative)

this is confusing could someone please explain how you bring numbers to imaginary powers and why you do it that way. I did not think you could bring a number to two separate powers and still have them equal the same number
Title: Re: Something you know
Post by: squidgetx on February 24, 2011, 05:28:43 pm
Actually no, n needs to be a multiple of 2. The reason for this is because, as Xeda said, e^ni= cos n + i sin n and the values of sin and cosine repeat themselves over a period of 2pi (Graph it to see). That part actually doesn't have to do with imaginary numbers.

Title: Re: Something you know
Post by: Deep Toaster on February 24, 2011, 05:30:38 pm
so what you are saying is that e^i*n*pi)-1=0 where n is any natural number(possibly negative)

Nope, e2nπi-1=0, while e(2n+1)πi+1=0.
Title: Re: Something you know
Post by: ruler501 on February 24, 2011, 05:33:25 pm
so it is e^(pi*2n*i)-1=0
while e^(pi*(2n+1)*i)+1=0

could somene please explain the proof behind bringing numbers to imaginary powers?
Title: Re: Something you know
Post by: Deep Toaster on February 24, 2011, 05:35:10 pm
http://en.wikipedia.org/wiki/Euler's_formula#Proofs

You'll need to know some calculus (as a warning).
Title: Re: Something you know
Post by: broooom on February 24, 2011, 05:35:35 pm
- Oops, wrong mathemathics used :P -
Title: Re: Something you know
Post by: Deep Toaster on February 24, 2011, 05:36:25 pm
That'd mean:

e^ip + 1 = 0
e^i * e^p = -1
e^i = -1/e^p
i = ln(-e^-p)
i = -p * ln(-e)
That can't be right! :o

It could be; remember ln(x) is undefined when x is negative.
Title: Re: Something you know
Post by: squidgetx on February 24, 2011, 05:37:24 pm
e^(pi i) does not equal e^(pi)*e^(i)

@ruler501, check this link: http://en.wikipedia.org/wiki/Euler's_formula#Proofs It's a bit hard to understand without a backing in calculus though :P

Generally you can't really conceptualize raising a number to an imaginary power; the main method of going about this sort of thing is creating a power series (a polynomial) that mimicks the behavior of e^x. e^x's power series (which, when taken to an infinite amount of terms is perfectly accurate) then can be used with imaginary values for x and still make sense.
e^x's power series looks like this:
(http://upload.wikimedia.org/math/2/b/8/2b8f73649758a53d36c2ed52cc30bbdd.png)
and so e^(ix)'s power series looks like this:
(http://upload.wikimedia.org/math/8/7/9/8799ab90dd91d47cf82ea7b449556230.png)
You'll have to take my word for it that that series is actually cosx+i*sinx. The rest of the proof goes from there.
Title: Re: Something you know
Post by: Deep Toaster on February 24, 2011, 05:38:50 pm
e^(pi i) does not equal e^(pi)*e^(i)

Didn't see that.

@ruler501, check this link: http://en.wikipedia.org/wiki/Euler's_formula#Proofs It's a bit hard to understand without a backing in calculus though :P

Ninja'd ;)

With almost the exact words :D
Title: Re: Something you know
Post by: apcalc on February 24, 2011, 05:42:10 pm
Ah yes!  That has to be the most beautiful mathematical statement that exists! :)

Although I still sometimes refuse to believe in its beauty, this (http://en.wikipedia.org/wiki/1_%E2%88%92_2_%2B_3_%E2%88%92_4_%2B_%C2%B7_%C2%B7_%C2%B7) still eludes me more! :)
Title: Re: Something you know
Post by: squidgetx on February 24, 2011, 05:43:56 pm
How about 1+2+3+4+....=-1/12 :D

Or 1+2^2+3^2+4^2+.....=0 O.o

Also @Deep, yeah I saw but I figured he didn't :P So I reposted it.
Title: Re: Something you know
Post by: Deep Toaster on February 24, 2011, 05:44:39 pm
Although I still sometimes refuse to believe in its beauty, this (http://en.wikipedia.org/wiki/1_%E2%88%92_2_%2B_3_%E2%88%92_4_%2B_%C2%B7_%C2%B7_%C2%B7) still eludes me more! :)

Whoa, what? O.O

And slightly off-topic: the Wikipedia URL is awesome too ;D

How about 1+2+3+4+....=-1/12 :D

Or 1+2^2+3^2+4^2+.....=0 O.o

:crazy: Where'd you get that?
Title: Re: Something you know
Post by: squidgetx on February 24, 2011, 05:50:05 pm
Wiki (http://en.wikipedia.org/wiki/1_%2B_2_%2B_3_%2B_4_%2B_%E2%80%A6)
Also, 1+1+1+1...=-1/2
Title: Re: Something you know
Post by: ruler501 on February 24, 2011, 06:00:44 pm
EDIT: Fixed the quote
Think about how you would do something like raising something to an imaginary power :D You can set up ratios and stuff and do more stuff and stuff. Also, e^(ix)=cos(x)+isin(x), so 3^i would be cos(ln(3))+isin(ln(3))

EDIT: so you can say with that the idea that e^(i2pi)-1=0 (that is i times 2 times pi)
So how would you calculate n^i with any real number for n
and then from that how would you calculate i^(ni)
None of these things work on my calculator so I'm wondering
@squidgetx I know that that factors into the two polynomial approximations for the trigonometric functions.

Does anyone one know anything that will help me learn more about/grasp imaginary numbers and things like raising things to imaginary powers?
Title: Re: Something you know
Post by: ruler501 on February 24, 2011, 06:03:38 pm
I was hoping to find/write a program that would do this but I see that that would be very hard to do

EDIT: I was asking about how Zeda got 3^i would be cos(ln(3))+isin(ln(3))
Title: Re: Something you know
Post by: squidgetx on February 24, 2011, 06:04:15 pm
Sorry I deleted my post, as it didn't make much sense. Yeah, i'm not quite sure how you would do it :P
Title: Re: Something you know
Post by: ruler501 on February 24, 2011, 06:07:23 pm
i edited my post above with what my question was
Title: Re: Something you know
Post by: Deep Toaster on February 24, 2011, 06:07:44 pm
Wiki (http://en.wikipedia.org/wiki/1_%2B_2_%2B_3_%2B_4_%2B_%E2%80%A6)
Also, 1+1+1+1...=-1/2

Math makes no sense. That's why I love it :D
Title: Re: Something you know
Post by: Juju on February 24, 2011, 06:12:02 pm
O_o how the hell adding an infinite number of positive numbers equals a negative one?

Math sure is weird.
Title: Re: Something you know
Post by: ruler501 on February 24, 2011, 06:12:25 pm
It does sometimes...
Other times it doesn't... other times=99.999999...% of the time(now lets see what does that equal)

EDIT: and I don't get the proof. why does it not equal infinity?
Title: Re: Something you know
Post by: Juju on February 24, 2011, 06:13:03 pm
It does sometimes...
Other times it doesn't... other times=99.999999...% of the time(now lets see what does that equal)
It equals 100%.
Title: Re: Something you know
Post by: Deep Toaster on February 24, 2011, 06:13:26 pm
99.999999...%

My calculator gives me a syntax error there.
Title: Re: Something you know
Post by: ruler501 on February 24, 2011, 06:14:32 pm
I wonder why it is the same as 0.999999999...=1 simple infinite series that don't switch signs and get less than the original when all operations are additiion
Title: Re: Something you know
Post by: phenomist on February 24, 2011, 06:52:08 pm
O_o how the hell adding an infinite number of positive numbers equals a negative one?

Math sure is weird.

Let's see if this rings a bell to programmers: It's a bit like signed numbers. 65535 = -1. 65535 = 1111111111111111 in binary. (in Axe. Sort of.)
Only in math, it's a perfect computer that has an infinite number of bits. But if you turn all of the bits on, then it becomes negative :D. 1+2+4+8+16+... = -1.

Well, maybe not, but that's the way I think of it. Still taking calculus, so I don't know the intricacies of this.

Also, strange followup: You've heard that you can't go colder below absolute zero, but it turns out that negative temperature is WARMER than an infinite amount of degrees. http://en.wikipedia.org/wiki/Negative_temperature
Title: Re: Something you know
Post by: ruler501 on February 24, 2011, 06:55:42 pm
the wikipedia link is broken

and I kind of understand how you could prove that
Title: Re: Something you know
Post by: jnesselr on February 24, 2011, 07:19:21 pm
If I had mod powers, I could fix it.  Just do:
Code: [Select]
[url=http://en.wikipedia.org/wiki/Negative_temperature]wiki[/url]
to get this: wiki (http://en.wikipedia.org/wiki/Negative_temperature)
Title: Re: Something you know
Post by: Xeda112358 on February 24, 2011, 11:44:38 pm
For raising to the imaginary power, you must work with positive real numbers (numbers that work with the natural log). If you want to use negatives to an imaginary power, you have to some even more advanced math playing :D so pretty much:
xi=cos(ln(x))+i*sin(ln(x))
Title: Re: Something you know
Post by: willrandship on February 25, 2011, 12:40:46 am
1+1+1+1+1+1+1+1+1+1+1+1...... as a signed int, when it reaches 32767 (or something) DOES become negative :P
Title: Re: Something you know
Post by: ralphdspam on February 25, 2011, 01:27:43 am
Yeah, but they were talking about real-life math, not 16-bit signed integers.  I still don't get it. How can 1+1+...=-1?
I will try it once i am finished dividing by 0.
Title: Re: Something you know
Post by: Xeda112358 on February 25, 2011, 01:28:35 am
because it is infinite bit :D
Title: Re: Something you know
Post by: ralphdspam on February 25, 2011, 01:31:52 am
Ok. That kind of makes sense in a sort of roundabout fashion. 
Title: Re: Something you know
Post by: Xeda112358 on February 25, 2011, 01:34:56 am
Yep, it is one of those things where it kind of almost nearly comes close to possibly being probably understandable in a drawn out roundabout way, just like you said :D Really, you could prove it to be anything which is why infinity is regarded more as a concept as opposed to a number.