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Math Help - rectangular and polar forms

  1. #1
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    rectangular and polar forms

    z1 = 2 + j2

    z2 = 1 + j5

    z3 = j6

    what is Y when :

    Y = (1/z1) + (1/z2) + (1/z3)

    1/z3 how is that done??????
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  2. #2
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    Re: rectangular and polar forms

    Multiply top and bottom by j.

    \frac{1}{Z_{3}}=\frac{1}{j6}=\frac{j}{j}.\frac{1}{  j6}=\frac{j}{-6}=-\frac{1}{6}j
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  3. #3
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    Re: rectangular and polar forms

    thanks bobp

    is this right what ive done so far
    1/z1 = 1/ (2+j2) = 0.25 - j0.25

    1/z2 = 1/ (1+j5) = 0.0385 - j0.1923

    1/z3 = j6 = j-1/6

    add them all together
    = 0.2885 - j-0.609
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  4. #4
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    Re: rectangular and polar forms

    Not totally correct, though the decimal values are correct.
    The end of that last line -j-0.609 would be interpreted as minus j minus 0.609, that is, two separate terms. And you have two negative signs when there should just be one.
    The correct form should be -j0.609 or -0.609j. I prefer the second one though I know the purists will say that the first is correct.
    You make more or less the same mistake in the 1/Z_{3} line immediately above. Write it as 1/Z_{3}=j(-1/6), it's a multiplication not a subtraction.
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