Function that halves the angle of a complex point












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How would a function mapping a complex point $z=re^{itheta}$ to $re^{ifrac{theta}{2}}$ be correctly written?










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    $begingroup$


    How would a function mapping a complex point $z=re^{itheta}$ to $re^{ifrac{theta}{2}}$ be correctly written?










    share|cite|improve this question









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      3












      3








      3





      $begingroup$


      How would a function mapping a complex point $z=re^{itheta}$ to $re^{ifrac{theta}{2}}$ be correctly written?










      share|cite|improve this question









      $endgroup$




      How would a function mapping a complex point $z=re^{itheta}$ to $re^{ifrac{theta}{2}}$ be correctly written?







      functions






      share|cite|improve this question













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      asked Dec 12 '18 at 20:18









      MatthewMatthew

      316




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          1 Answer
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          $begingroup$

          note that $|z|=r$, so I think the answer you are looking for (and you can test it yourself) is
          $$f(z)=|z|cdot left( frac{z}{|z|}right)^{frac{1}{2}}$$






          share|cite|improve this answer









          $endgroup$













          • $begingroup$
            Ok, so there is no easy way to get the angle of the complex point? I have seen somewhere that $Arg~z$ might be used as a notation for that, is that correct?
            $endgroup$
            – Matthew
            Dec 12 '18 at 20:29












          • $begingroup$
            This can be more succinctly written as $(|z|z)^{1/2}$.
            $endgroup$
            – eyeballfrog
            Dec 12 '18 at 20:36










          • $begingroup$
            @Matthew Yes, it's correct. To get the angle of $a+bi$ from the real axis, just draw a diagram and notice that $frac{b}{a}$ is its tangent.
            $endgroup$
            – timtfj
            Dec 12 '18 at 20:36












          • $begingroup$
            Yes I just wrote it out long way's so order of operations tells the story of what's happening. Also yes, $theta = tan^{-1}(frac{b}{a})$
            $endgroup$
            – NazimJ
            Dec 12 '18 at 20:38










          • $begingroup$
            Is it possible to define a function as $f(a+bi)=tan^{-1}(frac{b}{a})$, or is that incorrect notation?
            $endgroup$
            – Matthew
            Dec 12 '18 at 20:42













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          1 Answer
          1






          active

          oldest

          votes








          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          5












          $begingroup$

          note that $|z|=r$, so I think the answer you are looking for (and you can test it yourself) is
          $$f(z)=|z|cdot left( frac{z}{|z|}right)^{frac{1}{2}}$$






          share|cite|improve this answer









          $endgroup$













          • $begingroup$
            Ok, so there is no easy way to get the angle of the complex point? I have seen somewhere that $Arg~z$ might be used as a notation for that, is that correct?
            $endgroup$
            – Matthew
            Dec 12 '18 at 20:29












          • $begingroup$
            This can be more succinctly written as $(|z|z)^{1/2}$.
            $endgroup$
            – eyeballfrog
            Dec 12 '18 at 20:36










          • $begingroup$
            @Matthew Yes, it's correct. To get the angle of $a+bi$ from the real axis, just draw a diagram and notice that $frac{b}{a}$ is its tangent.
            $endgroup$
            – timtfj
            Dec 12 '18 at 20:36












          • $begingroup$
            Yes I just wrote it out long way's so order of operations tells the story of what's happening. Also yes, $theta = tan^{-1}(frac{b}{a})$
            $endgroup$
            – NazimJ
            Dec 12 '18 at 20:38










          • $begingroup$
            Is it possible to define a function as $f(a+bi)=tan^{-1}(frac{b}{a})$, or is that incorrect notation?
            $endgroup$
            – Matthew
            Dec 12 '18 at 20:42


















          5












          $begingroup$

          note that $|z|=r$, so I think the answer you are looking for (and you can test it yourself) is
          $$f(z)=|z|cdot left( frac{z}{|z|}right)^{frac{1}{2}}$$






          share|cite|improve this answer









          $endgroup$













          • $begingroup$
            Ok, so there is no easy way to get the angle of the complex point? I have seen somewhere that $Arg~z$ might be used as a notation for that, is that correct?
            $endgroup$
            – Matthew
            Dec 12 '18 at 20:29












          • $begingroup$
            This can be more succinctly written as $(|z|z)^{1/2}$.
            $endgroup$
            – eyeballfrog
            Dec 12 '18 at 20:36










          • $begingroup$
            @Matthew Yes, it's correct. To get the angle of $a+bi$ from the real axis, just draw a diagram and notice that $frac{b}{a}$ is its tangent.
            $endgroup$
            – timtfj
            Dec 12 '18 at 20:36












          • $begingroup$
            Yes I just wrote it out long way's so order of operations tells the story of what's happening. Also yes, $theta = tan^{-1}(frac{b}{a})$
            $endgroup$
            – NazimJ
            Dec 12 '18 at 20:38










          • $begingroup$
            Is it possible to define a function as $f(a+bi)=tan^{-1}(frac{b}{a})$, or is that incorrect notation?
            $endgroup$
            – Matthew
            Dec 12 '18 at 20:42
















          5












          5








          5





          $begingroup$

          note that $|z|=r$, so I think the answer you are looking for (and you can test it yourself) is
          $$f(z)=|z|cdot left( frac{z}{|z|}right)^{frac{1}{2}}$$






          share|cite|improve this answer









          $endgroup$



          note that $|z|=r$, so I think the answer you are looking for (and you can test it yourself) is
          $$f(z)=|z|cdot left( frac{z}{|z|}right)^{frac{1}{2}}$$







          share|cite|improve this answer












          share|cite|improve this answer



          share|cite|improve this answer










          answered Dec 12 '18 at 20:23









          NazimJNazimJ

          36317




          36317












          • $begingroup$
            Ok, so there is no easy way to get the angle of the complex point? I have seen somewhere that $Arg~z$ might be used as a notation for that, is that correct?
            $endgroup$
            – Matthew
            Dec 12 '18 at 20:29












          • $begingroup$
            This can be more succinctly written as $(|z|z)^{1/2}$.
            $endgroup$
            – eyeballfrog
            Dec 12 '18 at 20:36










          • $begingroup$
            @Matthew Yes, it's correct. To get the angle of $a+bi$ from the real axis, just draw a diagram and notice that $frac{b}{a}$ is its tangent.
            $endgroup$
            – timtfj
            Dec 12 '18 at 20:36












          • $begingroup$
            Yes I just wrote it out long way's so order of operations tells the story of what's happening. Also yes, $theta = tan^{-1}(frac{b}{a})$
            $endgroup$
            – NazimJ
            Dec 12 '18 at 20:38










          • $begingroup$
            Is it possible to define a function as $f(a+bi)=tan^{-1}(frac{b}{a})$, or is that incorrect notation?
            $endgroup$
            – Matthew
            Dec 12 '18 at 20:42




















          • $begingroup$
            Ok, so there is no easy way to get the angle of the complex point? I have seen somewhere that $Arg~z$ might be used as a notation for that, is that correct?
            $endgroup$
            – Matthew
            Dec 12 '18 at 20:29












          • $begingroup$
            This can be more succinctly written as $(|z|z)^{1/2}$.
            $endgroup$
            – eyeballfrog
            Dec 12 '18 at 20:36










          • $begingroup$
            @Matthew Yes, it's correct. To get the angle of $a+bi$ from the real axis, just draw a diagram and notice that $frac{b}{a}$ is its tangent.
            $endgroup$
            – timtfj
            Dec 12 '18 at 20:36












          • $begingroup$
            Yes I just wrote it out long way's so order of operations tells the story of what's happening. Also yes, $theta = tan^{-1}(frac{b}{a})$
            $endgroup$
            – NazimJ
            Dec 12 '18 at 20:38










          • $begingroup$
            Is it possible to define a function as $f(a+bi)=tan^{-1}(frac{b}{a})$, or is that incorrect notation?
            $endgroup$
            – Matthew
            Dec 12 '18 at 20:42


















          $begingroup$
          Ok, so there is no easy way to get the angle of the complex point? I have seen somewhere that $Arg~z$ might be used as a notation for that, is that correct?
          $endgroup$
          – Matthew
          Dec 12 '18 at 20:29






          $begingroup$
          Ok, so there is no easy way to get the angle of the complex point? I have seen somewhere that $Arg~z$ might be used as a notation for that, is that correct?
          $endgroup$
          – Matthew
          Dec 12 '18 at 20:29














          $begingroup$
          This can be more succinctly written as $(|z|z)^{1/2}$.
          $endgroup$
          – eyeballfrog
          Dec 12 '18 at 20:36




          $begingroup$
          This can be more succinctly written as $(|z|z)^{1/2}$.
          $endgroup$
          – eyeballfrog
          Dec 12 '18 at 20:36












          $begingroup$
          @Matthew Yes, it's correct. To get the angle of $a+bi$ from the real axis, just draw a diagram and notice that $frac{b}{a}$ is its tangent.
          $endgroup$
          – timtfj
          Dec 12 '18 at 20:36






          $begingroup$
          @Matthew Yes, it's correct. To get the angle of $a+bi$ from the real axis, just draw a diagram and notice that $frac{b}{a}$ is its tangent.
          $endgroup$
          – timtfj
          Dec 12 '18 at 20:36














          $begingroup$
          Yes I just wrote it out long way's so order of operations tells the story of what's happening. Also yes, $theta = tan^{-1}(frac{b}{a})$
          $endgroup$
          – NazimJ
          Dec 12 '18 at 20:38




          $begingroup$
          Yes I just wrote it out long way's so order of operations tells the story of what's happening. Also yes, $theta = tan^{-1}(frac{b}{a})$
          $endgroup$
          – NazimJ
          Dec 12 '18 at 20:38












          $begingroup$
          Is it possible to define a function as $f(a+bi)=tan^{-1}(frac{b}{a})$, or is that incorrect notation?
          $endgroup$
          – Matthew
          Dec 12 '18 at 20:42






          $begingroup$
          Is it possible to define a function as $f(a+bi)=tan^{-1}(frac{b}{a})$, or is that incorrect notation?
          $endgroup$
          – Matthew
          Dec 12 '18 at 20:42




















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