Modified tangent function











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I remember reading once of a modified arctangent function which was suited to be a chart on the circle. It should be defined something like



$$theta(x,y)=begin{cases}
arctan(frac{y}{x}) & x>0\
pi/2 & (x,y)=(0,1)\
-pi/2 & (x,y)=(0,-1)\
pi+arctan(frac{y}{x}) & x<0, y>0\
-pi+arctan(frac{y}{x}) & x<0, y<0
end{cases}$$



Can somebody remind me of its name?






trigonometry coordinate-systems







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    up vote
    0
    down vote

    favorite












    I remember reading once of a modified arctangent function which was suited to be a chart on the circle. It should be defined something like



    $$theta(x,y)=begin{cases}
    arctan(frac{y}{x}) & x>0\
    pi/2 & (x,y)=(0,1)\
    -pi/2 & (x,y)=(0,-1)\
    pi+arctan(frac{y}{x}) & x<0, y>0\
    -pi+arctan(frac{y}{x}) & x<0, y<0
    end{cases}$$



    Can somebody remind me of its name?






    trigonometry coordinate-systems







    share|cite|improve this question
























      up vote
      0
      down vote

      favorite









      up vote
      0
      down vote

      favorite











      I remember reading once of a modified arctangent function which was suited to be a chart on the circle. It should be defined something like



      $$theta(x,y)=begin{cases}
      arctan(frac{y}{x}) & x>0\
      pi/2 & (x,y)=(0,1)\
      -pi/2 & (x,y)=(0,-1)\
      pi+arctan(frac{y}{x}) & x<0, y>0\
      -pi+arctan(frac{y}{x}) & x<0, y<0
      end{cases}$$



      Can somebody remind me of its name?






      trigonometry coordinate-systems







      share|cite|improve this question













      I remember reading once of a modified arctangent function which was suited to be a chart on the circle. It should be defined something like



      $$theta(x,y)=begin{cases}
      arctan(frac{y}{x}) & x>0\
      pi/2 & (x,y)=(0,1)\
      -pi/2 & (x,y)=(0,-1)\
      pi+arctan(frac{y}{x}) & x<0, y>0\
      -pi+arctan(frac{y}{x}) & x<0, y<0
      end{cases}$$



      Can somebody remind me of its name?






      trigonometry coordinate-systems




      trigonometry coordinate-systems






      share|cite|improve this question













      share|cite|improve this question











      share|cite|improve this question




      share|cite|improve this question










      asked yesterday









      Iván Mauricio Burbano

      29218




      29218






















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          It appears to be known as $atan2(y,x)$ (the two-argument arctangent function).



          https://en.wikipedia.org/wiki/Atan2






          share|cite|improve this answer





















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            1 Answer
            1






            active

            oldest

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            active

            oldest

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            active

            oldest

            votes








            up vote
            2
            down vote



            accepted










            It appears to be known as $atan2(y,x)$ (the two-argument arctangent function).



            https://en.wikipedia.org/wiki/Atan2






            share|cite|improve this answer

























              up vote
              2
              down vote



              accepted










              It appears to be known as $atan2(y,x)$ (the two-argument arctangent function).



              https://en.wikipedia.org/wiki/Atan2






              share|cite|improve this answer























                up vote
                2
                down vote



                accepted







                up vote
                2
                down vote



                accepted






                It appears to be known as $atan2(y,x)$ (the two-argument arctangent function).



                https://en.wikipedia.org/wiki/Atan2






                share|cite|improve this answer












                It appears to be known as $atan2(y,x)$ (the two-argument arctangent function).



                https://en.wikipedia.org/wiki/Atan2







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered yesterday









                Eevee Trainer

                97111




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