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Math Help - Pre-Calc Graphing with Complex numbers. Multiplying with complex numbers.

  1. #1
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    Pre-Calc Graphing with Complex numbers. Multiplying with complex numbers.

    One question I need help with.

    If z=cisθ = r(cosθ + isinθ), show that (1/z) = (1/r)cis(-θ)
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  2. #2
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    You can use the following facts to prove it.
    \begin{array}{l}<br />
 z = r\left[ {cis\left( \theta  \right)} \right] \\ <br />
 \bar z = r\left[ {cis\left( { - \theta } \right)} \right] \\ <br />
  \end{array}

    \frac{1}{z} = \frac{{\bar z}}{{\left| z \right|^2 }}
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