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Math Help - The Impossible Factorisation

  1. #1
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    The Impossible Factorisation

    My friend and I are arguing again, about Maths (How cool are we?).

    Please, just assure me (and him), that you cannot factorise the equation:

    x^2 + 100

    So that there are two brackets, each with a value of x in.
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  2. #2
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    Quote Originally Posted by Bench. View Post
    Please, just assure me (and him), that you cannot factorise the equation:
    x^2 + 100
    That's not an equation. ALL equations have an = sign.

    (x+10)(x+10) - 20x
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  3. #3
    MHF Contributor red_dog's Avatar
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    It can't be factorized over \mathbb{R}, but it can be factorized over \mathbb{C}:

    x^2+100=(x-10i)(x+10i)
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  4. #4
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    Quote Originally Posted by red_dog View Post
    It can't be factorized over \mathbb{R}, but it can be factorized over \mathbb{C}:

    x^2+100=(x-10i)(x+10i)

    What is factorising over "C"?
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  5. #5
    Pim
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    R is the set of numbers you encounter in everyday life. This includes whole numbers, fractions and numbers like Pi. C is the set of all those and the complex numbers, which includes i, the root of -1.
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  6. #6
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    Fantastic. What does C and R stand for, if they stand for anything?
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  7. #7
    Pim
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    C stands for Complex, R for Real. (I think)
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  8. #8
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    Quote Originally Posted by Bench. View Post
    Fantastic. What does C and R stand for, if they stand for anything?
    You may want to do a search:

    N - natural numbers

    Z - integers

    Q - rational numbers

    R - real numbers

    C - complex numbers

    Its important to know what each set includes and its properties.
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