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Math Help - algebra help needed!

  1. #1
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    algebra help needed!

    The following quesitions regard complex numbers, thank you so much for helping.



    What are the coordinates of the complex number, i?


    When we add the two complex numbers a + bi and c + di by representing them as points in the complex plane, how would you express the sum?


    What is the absolute value of: -5 + 3i?

    What is the absolute value of: 3 - 2i

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  2. #2
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    Every complex number of the form a+bi can be seen as an ordered point (a,b) on the complex plane. For i, a=0, and b =1, so it is the point (0,1). Adding coordinates is exactly how it works in the normal coordinate plane.

    Absolute values of a complex number a+bi = \sqrt(a^2+b^2)
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  3. #3
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    reply

    no doubt your explanasion is correct, but you must of gathered that my math is quite week otherwise i wouldnt of joined this forum. I still dont really understand the second question i asked. Where you said when adding its just the same as standard coordinateds.


    What is the absolute value of: -5 + 3i? Would this be 8?

    What is the absolute value of: 3 - 2i Would this be 5?

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  4. #4
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    Absolute value of -5+3i is
    \sqrt(5^2 +3^2) = \sqrt(25+9)= \sqrt(31)

    I don't quite understand what they mean, but I guess it could be (a+b) +(c+d)i.
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