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Math Help - Complex Numbers Problem

  1. #1
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    Complex Numbers Problem

    The question is (8 + 20i) / (2i)
    So I think that I have to multiply that by (-2i)/(-2i), but I'm not sure?
    Also, It wants me to write the result in standard form?

    Any help is appreciated.
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  2. #2
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    Quote Originally Posted by tsmith View Post
    The question is (8 + 20i) / (2i)
    So I think that I have to multiply that by (-2i)/(-2i), but I'm not sure?
    Also, It wants me to write the result in standard form?

    Any help is appreciated.
    correct ... multiply numerator and denominator by the conjugate of 2i , which is -2i

    remember that i^2 = -1

    standard form is a + bi

    do it.
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  3. #3
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    (8+20i)/(2i) multiple (-2i)/(-2i) = (-16i - 40i^2)/(-4i^2) = (-16i+40)/(4) =
    -4i + 10

    Is this the correct answer?
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  4. #4
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    Quote Originally Posted by tsmith View Post
    (8+20i)/(2i) multiple (-2i)/(-2i) = (-16i - 40i^2)/(-4i^2) = (-16i+40)/(4) =
    -4i + 10

    Is this the correct answer?
    yes
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  5. #5
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    Here is one of the most important and over-looked ideas.
    \frac{z}{w} = \frac{{z\overline w }}{{\left| w \right|^2 }}.

    Thus: \frac{{8 + 2i}}{{2i}} = \frac{{\left( {8 + 2i} \right)\left( { - 2i} \right)}}{4}
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