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Math Help - algebra help needed!

  1. #1
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    algebra help needed!

    Regarding Complex Numbers:

    The Reciprical of i is?
    a. i
    b. -i
    c. does not exist
    d. 1+ i

    And Divide 3-i by 1+2i
    3-i/1+2i
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  2. #2
    A riddle wrapped in an enigma
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    Quote Originally Posted by 14041471 View Post
    Regarding Complex Numbers:

    The Reciprical of i is?
    a. i
    b. -i
    c. does not exist
    d. 1+ i

    And Divide 3-i by 1+2i
    3-i/1+2i
    Reciprocal of i

    i^{-1}=\frac{1}{i}\cdot\frac{i}{i}=\frac{i}{i^2}=\frac  {i}{-1}=-i

    \frac{3-i}{1+2i}\cdot\frac{1-2i}{1-2i}=\frac{3-i-6i+2i^2}{1-4i^2}=\frac{1-7i}{5}=\frac{1}{5}-\frac{7}{5}i
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