I Know This Is Flamewar Fuel But...

Post/Author/DateTimePost
#1

pigknight

Jan 06, 2011 20:17:46
Is 5 + 3i an imaginary number?
#2

Robin_Hoodlum

Jan 06, 2011 20:21:06
Is 5 + 3i an imaginary number?


I don't think so.
What does i represent? Simply an unknown number?
#3

pigknight

Jan 06, 2011 21:25:56
i is the square root of -1.
#4

salla

Jan 06, 2011 23:53:49
TECHNICALLY, no.

Technically, it is a complex number, consisting of a real part (the 5) and the imaginary part (the 3i).  On the other hand, an imaginary number can simply be thought of as a complex number where the real part is zero, and vice versa.
#5

Robin_Hoodlum

Jan 07, 2011 17:49:46
I always hated algebra.


I didn't mind Algebra or Trigonometry... but I hated Geometry.
#6

Ragnar_Lodbrok

Jan 07, 2011 17:54:14
*bursts in with a wrist-mounted flamethrower, a full-sized flamethrower, several tanks of napalm, and some thermite grenades* Oh. No flamewar .
#7

Sheffields_Park

Jan 07, 2011 19:55:06
Oh yeah well.....

I disagree!1!!!111bunchof1's!!1!11  L0l-cakez!  Rofl-copter!  1 c4n h4z ch33zburg3r!
#8

iqwinn

Jan 08, 2011 4:24:51
Sounds like how capitalists scientifically prove that it is the best system.



More like how communists scientifically prove that their system is the best.

Of course, when that fails to pass the BS meter, the commies haul out their guns and point them at their intended victims.  That's when it gets interesting...
#9

ADHadh

Jan 08, 2011 4:30:19

More like how communists scientifically prove that their system is the best.

Of course, when that fails to pass the BS meter, the commies haul out their guns and point them at their intended victims.  That's when it gets interesting...


Unless they are Chinese or something.
And the recent crisis showed a lot of BS as well.

On math: I never minded it much. It became difficult only after I got to a technology university.
Of course my math skills have deteriorated with time.
#10

EscherEnigma

Jan 08, 2011 14:08:53
... ?
Um... any real-world application of algebra isn't finding numbers for the sake of finding numbers.  It's finding a number because it's useful.
#11

iqwinn

Jan 09, 2011 3:21:17
Trig and geometry are very useful for machinists.  I remember one of my instructors saying that when computer numeric controlled machines were first being built and programmed, programmers had to memorize the value of pi (Π), out to 16 digits.
#12

ORC_Nashira

Jan 09, 2011 11:34:32
Please keep your posts polite, respectful and refrain from personal attacks and flaming, these are violations of the Code of Conduct.  You can review the Code here: wizards.custhelp.com/cgi-bin/wizards.cfg... . You are welcome to disagree with one another but please do so respectfully and constructively.

************
#13

jesse.two.coins

Jan 10, 2011 6:57:33
Please keep your posts polite, respectful and refrain from personal attacks and flaming, these are violations of the Code of Conduct.  You can review the Code here: wizards.custhelp.com/cgi-bin/wizards.cfg... . You are welcome to disagree with one another but please do so respectfully and constructively.

************



lol wut?
#14

EscherEnigma

Jan 10, 2011 23:13:24
[...] as it shows that what I said cannot be refuted.


Not really.

It doesn't prove anything.  That's kinda the reason it's bad debate tactics.
#15

mc-drowbane

Jan 11, 2011 0:14:20
I think it's because Goldy had some smart-@$$ comment on what I said about communists, something that ORC_Nashira saw as a personal attack and deleted.

I don't worry too much about ad hominem attacks, as it shows that what I said cannot be refuted.




Please. It is only because you didn't like my rebuttle. You linked weapons and communist and I linked weapons and right-wingers who shoot politicians. But right-wingers do not like the truth so they just censore stuff because they cannot debate and face truth. I am glad that big brother ORC helped you. Pretty ironic since you believe that higher authorities can only abuse their power. I guest it only aplays to stuff you do not like.



Wow.  And no, I'm not referring to the life destroying game.

Internet be damned.

In goldomark's defense; everything can be refuted.

In ORC_nashira's defense; doing the job.

In iquinn's defense; opinions will always be met with adversity.  Especially if they are expressed.

Can't we all just agree to disagree?

We're all pretty here.




#16

Qube

Jan 11, 2011 1:17:59
Is 5 + 3i an imaginary number?


its not a number. '+' is not a valid mathematical sign. 
#17

Klirshon

Jan 11, 2011 6:07:10
If the Piggles really wanted to push the boundary towards a mathematical flame-war, he should have brought up the cliched "does 0.9999... equal 1" debate. Humans argue over the most inane subjects.
#18

pluisjen

Jan 11, 2011 6:09:41
does 0.9999... equal 1



That one's fun. I'm still of the opening they're the same, but it's always fun to see counter-arguments. 
#19

ADHadh

Jan 11, 2011 6:18:48
does 0.9999... equal 1



That one's fun. I'm still of the opening they're the same, but it's always fun to see counter-arguments. 


It's not 1 in the stricktest sense, but it could be treated as 1 for practical reasons
#20

pluisjen

Jan 11, 2011 6:25:39
You can actually prove it's 1. Check this:

X = 0.99999999999999...
-> multiply by 10
10X = 9.9999999999... 
-> minus X
9X = 9
-> divide by 9
X = 1

So it's actually exactly the same. But you can still argue it's not the same, based on which rules for calculating with Infinites you follow... not everyone agrees on those.
#21

zombie_babies

Jan 11, 2011 9:25:42
My post done got et.  What a world, what a world.

EDIT: Your post may be safe, Plu.  I quoted and you did not.  We'll see what happens. 

EDITAGAIN: Oh, and I do agree with you.  I was just irritated by someone using a personal interpretation of a recent event as some sort of definitive proof.

EDITSOMEMORE: Wikileaks task force?  The post I quoted is still there but mine is gone.  That's just ... wikileaks task force.  Damn.
#22

iqwinn

Jan 11, 2011 10:22:47
I just saw the ± sign...d'oh!

While not an accepted mathematical symbol, it is espressive of a deviation, in statistics and as they are used by machinsts, tool-makers, and engineers.
#23

homicidal_squirrel

Jan 11, 2011 10:32:25
The ± sign just means plus (+) or minus (-). There are actually two equations being presented.
The question should really be "are 5 + 3i or 5 - 3i an imaginary numbers?"   
#24

Klirshon

Jan 11, 2011 11:28:40
The ± sign just means plus (+) or minus (-). There are actually two equations being presented.
The question should really be "are 5 + 3i or 5 - 3i an imaginary numbers?"   



Qube was being a "smartaleck" as Piggles used the underline command for an addition symbol instead of "±" .

Error: False presumption, Piggles used the proper symbol. Qube just doesn't acknowledge of the symbol as proper in mathematics.

Sensory data corrupted: I need to hibernate soon...
#25

orc_jade

Jan 11, 2011 11:35:03
Please keep your posts polite, respectful, and on-topic.
#26

ADHadh

Jan 11, 2011 11:44:01
It's still valid, it's just not an equation (never was).
It could be read as "is 5, give or take 3i, an imaginary number?"
It still doesn't sound right though.
Proper question should probaby be "is a belonging to A where A={x: x

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≤5+3i} an imaginary number?"
(sorry for lack of actual symbols, didn't know how to put them in"


#27

Qube

Jan 12, 2011 4:06:29
off topic:
You can actually prove it's 1. Check this:

X = 0.99999999999999...
-> multiply by 10
10X = 9.9999999999... 
-> minus X
9X = 9
-> divide by 9
X = 1

Sorry Plu, but there's a capital mistake in this proof (I bolded it): You may not substract unknown variables.

It's just like 'divide by X'. Unless you first can prove that you may divide by X (a.k.a. that X can't be zero), you can't divide by X.
Same here: We're trying to calculate the value of  0.9999... (or X). But suppose the numerical value of 0.9999 actually equals infinity (instead of 1) ...

You just did '10X-X', which comes down to infinity minus infinity, which can't be done.
X = inf
10X = inf
10X-X = inf-inf
9X = 9
X = 1. which is wrong, as X was inf


#28

pluisjen

Jan 12, 2011 4:14:39
How is X an unknown variable? It's 0.999999...

That doesn't look very unknown to me.

The proof is also given on the Wiki page along with a series of other proofs :P
en.wikipedia.org/wiki/0.999... 

Anyway my formal math training isn't done yet for the time being, so I'll probably learn a few things as I proceed.
#29

Qube

Jan 12, 2011 4:42:38
How is X an unknown variable? It's 0.999999...

but the point is that we don't know what 0.999999... is, ins't it? (because you're proving its actually 1)

You're assuming its a real number, so you assume you can use real operations


  • you can multiply any real number with an other real number (if you have X, you can do 10*X)

  • you can add any real number with an other real number

  • you can substract any real number with an other real number

  • you can only divide by a real number, if that number is not zero


However, unless you first prove (or assume) that 0.999999... real number, you can't  do such operations.

And that is what the wikipedia page you linked says: "0.999... denotes a real number that can be shown to be the number one." So on the wikipage, they start with the base assumption that 0.999 is the (real) number 1.

By defining "0.999... denotes a real number that can be shown to be the number one", I can show a much shorter proof:  "0.999... equals 1". By definition. Q.E.D.



However, To give an other example, if I define 0.999... as

Limit(X->positive infinity) for 1-1/(10 to the power X)
.

Then, mathematically, the only correct statement is that

0.999... approaches 1, as opposite to 0.999... equals 1.

(which, btw also uses the '=' sign; to confuse people ... )
#30

pluisjen

Jan 12, 2011 5:00:18
Actually, what they assume, is only that it's a real number, and from that assumption you can prove that if it's a Real, then it equals 1.

But anyway, this is what I meant about being able to discuss it for so long... it's both exactly 1 and not exactly 1 at the same time.
#31

EscherEnigma

Jan 12, 2011 13:23:02
This sounds like one of those proofs that shows women are evil1, or that 2 = chair.

Thing is though, that I'm not a "scientist"2, I'm an "engineer".  Which, naturally, brings us back to the old joke about the difference between a mathematician and the mechanic4, which illustrates the difference between applied and theoretical.
________
1Let's see... I think it goes something like...
Women = time * money ("Women take time and money")
Since time = money ("time is money, friend!")
Women = money2
Since money = evil1/2 ("money is the root of all evil")
Women = (evil1/2)2
Women = evil
2Well, it says "computer science" on my diploma3, but any career I actually get will probably have "computer engineer" as the description, as opposed to "computer scientist".
3Or rather, it will once I get it.  Registrar's office said they'll be mailed the 15th...
4A mathematician and a mechanic are both at a line, with a beautiful naked woman at the other end of the room.  They are told that with each step they can halve the difference between them and the woman, but never more then that.  They can take an unlimited number of steps.  The mathematician exclaims "But we'll never get there!" to which the mechanic replies "but we can get close enough."

Disclaimer: I apologize for the sexist jokes in this post.  I blame my math-major friend.  She liked the sexist math jokes for some reason.
#32

Klirshon

Jan 13, 2011 0:09:28
My parameters are curious: how do you equate two with chair?
#33

EscherEnigma

Jan 13, 2011 0:16:42
I can't remember, but the math majors found the proof hilarious.
#34

Qube

Jan 13, 2011 3:02:49
A mathematician and a mechanic are both at a line, with a beautiful naked woman at the other end of the room.  They are told that with each step they can halve the difference between them and the woman, but never more then that.  They can take an unlimited any number of steps.  The mathematician exclaims "But we'll never get there!" to which the mechanic replies "but we can get close enough."

fixed

if the mathematician can take an unlimited amount of steps, he's in a collection of numbers superceiding the real numbers (being the real numbers and infinity, R U {+inf,-inf}.  ( R being the collection of real numbers) )

While in R you need limits to work with infinity (and thus the mathematican will only be able to get near the woman), in R U {+inf,-inf}, you can work with infinity as a number. As such


  • 2(+infinity) equals (+infinity) 

  • 1/(+infinity) equals zero


So, when taking an unlimited amount of steps, the distance between the woman and the mathematican will equal (1/2(+infinity)) which equals zero. So the mathematican would get there


Though the physisist will point out that the mathematican will die before getting there ...