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How old is i? (Imaginary number)

  1. Mar 26, 2015 #1
    A couple of things I've read or heard in class suggest it's been around for a very long time. I got the impression it's from antiquity, but am I wrong?
     
  2. jcsd
  3. Mar 26, 2015 #2

    DaveC426913

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    Well, Wiki suggests the Greeks had it.

     
  4. Mar 26, 2015 #3
    Interesting, any idea how right this is?
     
  5. Mar 27, 2015 #4

    Mark44

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    How right what is? Do you have a specific question about the wiki article?
     
  6. Mar 27, 2015 #5
    Well wiki can be really wrong at times, and I was wondering if anything seemed amiss.
     
  7. Mar 27, 2015 #6

    Mark44

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    It's a pretty short article -- I don't see anything that jumps out at me as being wrong.
     
  8. Mar 27, 2015 #7

    epenguin

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    It's an oft told tale, the idea was come across by Italian mathematicians Tartaglia, Cardano, Bombelli (who actually did what is a complicated story) in the Renaissance, in the 16th century. Arguably the most important peice of math ever done, no one will dispute one of the most.

    Complex numbers can now be given a concrete image you probably know and made fairly obvious. Used by engineers and practical people every day. But that was only thought of centuries later. At the time it was just the square root of minus one which "obviously can't exist" but suspending disbelief if it existed they could use it in calculations (namely for solving cubic equations) and get just real number results, it worked! They called it strange names like "less of minus" or something. I think that was the first time they ever worked with such a thing of which there was no concrete model, that makes it quite pathbreaking, and set a new pattern for math, which is why it is so important.

    They didn't like having to do it, and for a long time they thought it was a temporary expedient or shortcut, till they could find a more satisfactory way of solving cubics etc. I read it has been proved There Is No Alternative, that hey cannot be avoided in solving cubics and other problems - I don't know how advanced that proof is.

    I am writing this from memory but there are loads of books on this history.
     
  9. Mar 27, 2015 #8

    SteamKing

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  10. Mar 27, 2015 #9

    DaveC426913

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    Emboughtened. Thank you.
     
  11. Mar 27, 2015 #10
    I may actually read it it sounds fascinating.
     
  12. Mar 28, 2015 #11

    epenguin

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    Bombelli's father was hanged in the public square in Bologna (for political, not criminal, offences). Not a lot of people know that.
    I met the man discovered that in the archives. It's now in a book I have somewhere - but that is getting as hard to find as it was in the original archives. :frown:
     
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