Breaking a path, in 2 integrals












0












$begingroup$



Let $overrightarrow V, Gamma$, be a vectorial field and a path such that:



$$overrightarrow V=-(x^2+y^2)overrightarrow i-(x^2-y^2)overrightarrow j$$



and



$$Gamma={(x,y)inmathbb{R}^2 | x^2+y^2=4, y < 0}cup {(x,y)inmathbb{R^2}| (x-1)^2+y^2=1, y geq0}$$




I know that: $int_{Gamma}overrightarrow V doverrightarrow r=int_{Gamma}Pdx+Qdy$



$P(x,y)=-x^2-y^2$



$Q(x,y)=y^2-x^2$



I'm going to use this parametrization to calculate this:



$x(t)=2cos t$



$y(t)=2sin t$



$tin[pi,2pi]$



But that is only for the first part of the path can I calculate the first part of the path with a parametrization and the second one of the path with another parametrization?










share|cite|improve this question









$endgroup$

















    0












    $begingroup$



    Let $overrightarrow V, Gamma$, be a vectorial field and a path such that:



    $$overrightarrow V=-(x^2+y^2)overrightarrow i-(x^2-y^2)overrightarrow j$$



    and



    $$Gamma={(x,y)inmathbb{R}^2 | x^2+y^2=4, y < 0}cup {(x,y)inmathbb{R^2}| (x-1)^2+y^2=1, y geq0}$$




    I know that: $int_{Gamma}overrightarrow V doverrightarrow r=int_{Gamma}Pdx+Qdy$



    $P(x,y)=-x^2-y^2$



    $Q(x,y)=y^2-x^2$



    I'm going to use this parametrization to calculate this:



    $x(t)=2cos t$



    $y(t)=2sin t$



    $tin[pi,2pi]$



    But that is only for the first part of the path can I calculate the first part of the path with a parametrization and the second one of the path with another parametrization?










    share|cite|improve this question









    $endgroup$















      0












      0








      0





      $begingroup$



      Let $overrightarrow V, Gamma$, be a vectorial field and a path such that:



      $$overrightarrow V=-(x^2+y^2)overrightarrow i-(x^2-y^2)overrightarrow j$$



      and



      $$Gamma={(x,y)inmathbb{R}^2 | x^2+y^2=4, y < 0}cup {(x,y)inmathbb{R^2}| (x-1)^2+y^2=1, y geq0}$$




      I know that: $int_{Gamma}overrightarrow V doverrightarrow r=int_{Gamma}Pdx+Qdy$



      $P(x,y)=-x^2-y^2$



      $Q(x,y)=y^2-x^2$



      I'm going to use this parametrization to calculate this:



      $x(t)=2cos t$



      $y(t)=2sin t$



      $tin[pi,2pi]$



      But that is only for the first part of the path can I calculate the first part of the path with a parametrization and the second one of the path with another parametrization?










      share|cite|improve this question









      $endgroup$





      Let $overrightarrow V, Gamma$, be a vectorial field and a path such that:



      $$overrightarrow V=-(x^2+y^2)overrightarrow i-(x^2-y^2)overrightarrow j$$



      and



      $$Gamma={(x,y)inmathbb{R}^2 | x^2+y^2=4, y < 0}cup {(x,y)inmathbb{R^2}| (x-1)^2+y^2=1, y geq0}$$




      I know that: $int_{Gamma}overrightarrow V doverrightarrow r=int_{Gamma}Pdx+Qdy$



      $P(x,y)=-x^2-y^2$



      $Q(x,y)=y^2-x^2$



      I'm going to use this parametrization to calculate this:



      $x(t)=2cos t$



      $y(t)=2sin t$



      $tin[pi,2pi]$



      But that is only for the first part of the path can I calculate the first part of the path with a parametrization and the second one of the path with another parametrization?







      integration vector-fields parametrization






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      asked Jan 13 at 11:26









      C. CristiC. Cristi

      1,629218




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          $begingroup$

          Your path is in fact the union of two different ones: the lower semicircle $;x^2+y^2=4;$ and the upper semicircle $;(x-1)^2+y^2=1;$ . For the first one you can parametrize (in the positive direction)



          $$Gamma_1: r_1(t)=(2cos t,,2sin t);,;;tin[pi,2pi];$$



          and the second one



          $$Gamma_2: r_2(t)=(1+cos t,,sin t);,;;tin[0,pi]$$



          Usually paths given are path connected, yet this one isn't....anyway, now you can integrate on each separatedly.






          share|cite|improve this answer









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            $begingroup$

            Your path is in fact the union of two different ones: the lower semicircle $;x^2+y^2=4;$ and the upper semicircle $;(x-1)^2+y^2=1;$ . For the first one you can parametrize (in the positive direction)



            $$Gamma_1: r_1(t)=(2cos t,,2sin t);,;;tin[pi,2pi];$$



            and the second one



            $$Gamma_2: r_2(t)=(1+cos t,,sin t);,;;tin[0,pi]$$



            Usually paths given are path connected, yet this one isn't....anyway, now you can integrate on each separatedly.






            share|cite|improve this answer









            $endgroup$


















              1












              $begingroup$

              Your path is in fact the union of two different ones: the lower semicircle $;x^2+y^2=4;$ and the upper semicircle $;(x-1)^2+y^2=1;$ . For the first one you can parametrize (in the positive direction)



              $$Gamma_1: r_1(t)=(2cos t,,2sin t);,;;tin[pi,2pi];$$



              and the second one



              $$Gamma_2: r_2(t)=(1+cos t,,sin t);,;;tin[0,pi]$$



              Usually paths given are path connected, yet this one isn't....anyway, now you can integrate on each separatedly.






              share|cite|improve this answer









              $endgroup$
















                1












                1








                1





                $begingroup$

                Your path is in fact the union of two different ones: the lower semicircle $;x^2+y^2=4;$ and the upper semicircle $;(x-1)^2+y^2=1;$ . For the first one you can parametrize (in the positive direction)



                $$Gamma_1: r_1(t)=(2cos t,,2sin t);,;;tin[pi,2pi];$$



                and the second one



                $$Gamma_2: r_2(t)=(1+cos t,,sin t);,;;tin[0,pi]$$



                Usually paths given are path connected, yet this one isn't....anyway, now you can integrate on each separatedly.






                share|cite|improve this answer









                $endgroup$



                Your path is in fact the union of two different ones: the lower semicircle $;x^2+y^2=4;$ and the upper semicircle $;(x-1)^2+y^2=1;$ . For the first one you can parametrize (in the positive direction)



                $$Gamma_1: r_1(t)=(2cos t,,2sin t);,;;tin[pi,2pi];$$



                and the second one



                $$Gamma_2: r_2(t)=(1+cos t,,sin t);,;;tin[0,pi]$$



                Usually paths given are path connected, yet this one isn't....anyway, now you can integrate on each separatedly.







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered Jan 13 at 11:58









                DonAntonioDonAntonio

                178k1494230




                178k1494230






























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