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  1. #1 |x| 
    Member pienapple27's Avatar
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    Is it correct to define |x| as the distance from zero to x?
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    It's also the distance from zero to minus x.
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    If that is true, can I say ?
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    I take it x is just an ordinary, real number? That isn't really the definition, which is this (for real x):


    However, more often than not you would define the "distance" between the real numbers x and y as |x - y|, so in essence you are right.

    Edited to add: Ah, I just saw your second post. If x can be complex, the notation |x| is use for the modulus of x, which in terms of the real and imaginary parts of x is


    By Pythagoras' theorem, |x| is the length of the arrow representing x in the Argand plane. For values of x which happen to lie on the real axis, this definition coincides with the first definition I gave above.
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    What about complex numbers? Would give me the "size" of the number or what?

    P.S.- Look at that! I learned how to use the tex tags xD
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    btr
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    Quote Originally Posted by pienapple27 View Post
    What about complex numbers? Would give me the "size" of the number or what?
    Yep (I edited my previous post to cover this - see above).

    Quote Originally Posted by pienapple27 View Post
    P.S.- Look at that! I learned how to use the tex tags xD
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    Just to wrap it up:
    Complex number --> , being a the real part and b the imaginary part.

    Ex:


    That's 'bout it right?

    P.S.- I've edited this 100 times but I can't get my square root to go over all the stuff in parenthesis like you did. What's the secret?
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    btr
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    Quote Originally Posted by pienapple27 View Post
    Just to wrap it up:
    Complex number --> , being a the real part and b the imaginary part.

    Ex:


    That's 'bout it right?
    Yes, that's it.

    Quote Originally Posted by pienapple27 View Post
    P.S.- I've edited this 100 times but I can't get my square root to go over all the stuff in parenthesis like you did. What's the secret?
    You need curly braces, like this: [tex]\sqrt{1^2 + 2^2}[/tex].

    By the way, if you ever want to see how a LaTeX formula was written by someone, try double-clicking on it. It should bring up the LaTeX code.
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    Oh cool, thanks!
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