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The Simpsons mathematic geek received no attention

  1. Jun 23, 2008 #1
    I remember an episode of The Simpsons, where a mathematic geek received no attention of his fellow peers, so he shouted: PI IS EXACTLY THREE!
    I just couldn't help laughing:D

    OK, over to my recent low-leveled mathematics-discovery, regarding whether i is not equal to 1, -1 nor anything like that.

    I first wrote this, to ensure I understood the principle:
    9^0.5 = 3
    9^0.5*9 = 3*9
    27 = 27

    Now, over to the subject:
    i^4 = 1
    1^0.25 = i
    (1^0.25)*1*1*1 = (i*1*1*1) //here's the issue
    1 = i

    I didn't even get here earlier, I was trapped in my own confusing thinking, though when I ended up here - I saw the flaw at once..
    But now, I forgot it o_O
    Anyone'd like to refresh me?
    I can't use the Google calculator either, since it doesn't show flaws, it only calculates what you put in on one side, not both.
  2. jcsd
  3. Jun 23, 2008 #2
    What, that makes no sense.[tex]i=\sqrt{-1}[/tex]

    1^0.25=1 not i.
  4. Jun 23, 2008 #3


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    What exactly is the problem?

    i^4=1 for i=1
    i^.25=1 for i=1

  5. Jun 23, 2008 #4


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    Not necessarily. I mean, he might be referring to i, but who says he isn't simply using the variable i?
  6. Jun 23, 2008 #5

    i is *one* of the fourth roots of 1, the others being 1, -1 and -i.

    Okay, so you multiply each side by 1 three times...

    Does not follow from the previous line. The previous line just returns the same equation you had before you started: 1^0.25 = i.

    I think the issue is that you're mixing roots of 1 here. There are four fourth roots of 1: 1, -1, i and -i. If you take any of these to the fourth power, you'll get one. But that does NOT mean that any product of four of these terms gives 1, nor that they're equal to one another. It seems to me that the fundamental error here is confusion of the multiplicity of roots.
  7. Jun 23, 2008 #6
    Or you can just think about it visually. I don't really get what the post is for, but just visualize a unit circle on the complex plane.

    Then it's just going to alternate between 1 and -1 for each even exponent of i with i^0 = 1. This comes from Euler's formula.
  8. Jun 23, 2008 #7

    D H

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    How many times do we have to go over this with you?

    You can use the search tool to find your own posts, and thence find the answer.

    The problem is that you are ignoring that 1^0.25 has four roots. There is nothing special about imaginary numbers going on here. The exact same faulty reasoning can lead you to conclude that -1=1 because (-1)^2=(1)^2. It is faulty reasoning. You can conclude [tex]a^r=b^r \,\Rightarrow\,a=b[/tex] if a and b are positive real numbers and r is real. You cannot conclude this if any of the values is complex or if a or b is negative.
  9. Jun 23, 2008 #8


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    Question to the OP for clarity:

    Is this about complex numbers and the root of -1, or not?
  10. Jun 23, 2008 #9

    D H

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    Dave, if you look at the other threads started by the OP you will see that this is about the root of -1.

    https://www.physicsforums.com/search.php?searchid=1168683 [Broken]
    Last edited by a moderator: May 3, 2017
  11. Jun 24, 2008 #10
    Re: i=1

    With real positive numbers, like I used in my first example, you can solve this:
    a^0.x by multiplying the number with itself, relative to its exponent, for example:

    Then with a lower exponent:
    1594323 = 1594323

    Therefor it would follow if it was a real positive number. <-- with a negative, it becomes complex again

    I guess my point/the conclusion is that there's several 'formulas' for real numbers, that doesn't work with complex numbers...
    And that just.. not surprises, but amazes me; it's interesting, since i is actually somehow a "real number" (I've been trying to figuring this out as well).
    i is (-)^0.5 1 or whatever you'd like to call it.
    It's not negative nor positive, until multiplied with itself, which is just an absurd idea from the beginning of, and again interesting.

    It is.
    Also I didn't know there were a way to say "for i=1" ;o
    Thanks, now I know that too x)
    I'm not very educated, 17 years old, done primary school for 9 years, stopped with homework @ 5th grade, I'm just trying to get back :D

    And D H
    The issue you're addressing, is something I figured out already in the beginning, this thread is therefor not about that.
    Last edited: Jun 24, 2008
  12. Jun 24, 2008 #11


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    And what happens if I write 81^0.5=-9?

    Your question has been answered in posts #5 & #7. Please read them carefully. This has nothing do do with i "being special" and has everything to do with multiple roots and principal values.
  13. Jun 24, 2008 #12


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    Re: i=1

    No, it doesn't follow. In the real numbers, with x a positive real number, [itex]x^{1/n}[/itex] is defined as the positive real number whose nth power is x (the "principal" root). That is NOT the definition for a negative real number which has NO "principal" root.

    Last edited by a moderator: Jun 24, 2008
  14. Jun 24, 2008 #13
    Re: i=1

    Dark Fire: Be very careful. With your personality, you're at risk of becoming what most people would call a crack pot. It's not a bad thing (and it's certainly not inevitable), I'm the same way some times, but you should be aware of it. To avoid this, you need to listen to what other people are saying. Don't just post something so that you can get validity; read what people are saying and try to understand the mistakes that people are pointing out. Also, try not to immediately trust your own results (I've seen you with other similar posts where you'll write a "proof" that 1 = -1 and ask why it is the case. However, it's not. 1 = -1 is completely false.) because you can certainly be wrong. If you come up with some result that seems wrong, there's a very good chance that it is and that you've made some mistake somewhere. Even if you come up with something that is correct, it does not mean that the logic you used to arrive there is correct.

    Most importantly: Don't be afraid to make mistakes, but accept that you can, have, and will continue to make them. Most people in any profession (especially science and mathematics) would be more surprised to learn that they haven't made a mistake than to find that they made several. With practice though, people learn to avoid the larger mistakes and how to spot others so that they know that their mistakes are probably small. But even then, most people know that even small mistakes can completely ruin the result. You're not yet at this point with mathematics, so try to be aware of this.
    Last edited: Jun 24, 2008
  15. Jun 24, 2008 #14
    Re: i=1

    This is deeper than that I'm not aware of "denial"/to ignore others statements.
    "nth power of blabla" <-- wtf..? power of = exponent, n = real number?
    I'm living in a very emotional place, with emotional people, I'm trying hard not to burst out in anger or sadness, and instead of going mad, and then possibly come with shallow, angry statements, I just ignore whatever I need to, to not burst out~

    I need a clearcut, easy-English statement that explains not the obvious, but the complex - the part of the equation I don't get, or I'm having trouble with~
    I've probably written this a 100 times, but I live not in an English-speaking country, also I never payed attention to school; what seem to be a possibly great vocabulary (or not) is nothing but what I've learned the last year through Googling and games, I could barely write and say simple words such as: yes, no, bye, what - a couple of years ago.
    While my life's gotten just worse and worse, I've gotten less and less space of learning, and I've ended up barely Googling anything, though I'm still philosophizing sometimes, and solving math puzzles, since it steals no energy for me to philosophize, rather than figuring out, for example how a Buffer Overflow actually works by source (not just the idea, but in practice).

    I'm just trying to focus at something else, since there's no way I can solve my problems IRL, and I just have to keep acting shallow, a "crack pot".

    Thanks for your concerns, though.

    Oh, and another thing: I also got bad experiences about people that sighs @ me all the time, mom, teachers, I guess we 'all' experience that, but since I've never felt hope - I quit acting out, I guess.
    Rather just change the subject than experiencing a million sighs, like they're truly my superior, and I'm worthless.

    Enough about me now >_<
    Thanks for replies.
  16. Jun 24, 2008 #15

    matt grime

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    Re: i=1

    Well, if you are asking 'where have I gone wrong', then the answer is there. (The line you wrote after this also makes no sense.)

    There is nothing to justify that this assertion is true; it isn't as it happens since the principal (not principle) root is taken to be the positive real root anyway.
  17. Jun 24, 2008 #16


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    Re: i=1

    So what are you trying to say? You have been given the answer to your problems several times in this thread. Are you just intending on ignoring them?
  18. Jun 24, 2008 #17
    Re: i=1

    1^0.25=i is wrong?
    The line after is what I'm using to make a number with an exponent lower than 1 to become 1, though with complex numbers, as you can see, doesn't work.
    If you watch the first line (9^0.5=3)-thingy, u can find the method~
  19. Jun 24, 2008 #18
    Re: i=1

    If not written in a clearcut, satisfying way, then yes.

    Sorry about double post
  20. Jun 24, 2008 #19

    D H

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    Re: i=1

    What's even frustrating is that he has raised this same issue in three other threads, has been answered multiple times in each and every one of those threads, and has ignored all of those answers. Sigh.
  21. Jun 24, 2008 #20

    matt grime

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    Re: i=1


    And it doesn't make any sense. At best you're claiming (by adding powers in the exponent on the left hand side) that


    Since you're arbitrarily choosing roots at will there is no logical reason to suppose that this equality holds, or even makes sense. It is, in fact, equivalent to you asserting that since 1 and -1 square to the same number, then 1=-1. As is frequently the case, light can be shed on the problem without recourse to the overly complicated ideas initially used. The infamous James Whatisisname (honestly can't remember) was a prince of this on sci.math with his "over-interpretation of galois theory".
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