A specific example of $F$-related vector fields












3














I need to prove the following:



Let $F:Bbb{R}toBbb{R}^2$ be the smooth map $F(t)=(cos t,sin t)$. Then $d/dtinmathcal{T}(Bbb{R})$ is $F$-related to the vector field $Zinmathcal{T}(Bbb{R}^2)$ defined by $$Z=xfrac{∂}{∂y}-yfrac{∂}{∂x}.$$



So for any smooth $f$ defined on an open subset of $Bbb{R}^2$ we want $$frac{d}{dt}(fcirc F)=(xfrac{∂}{∂y}f-yfrac{∂}{∂x}f)circ F.$$ That is,$$frac{∂}{∂x}ffrac{d}{dt}F+frac{∂}{∂y}ffrac{d}{dt}F=(xfrac{∂}{∂y}f-yfrac{∂}{∂x}f)circ F.$$ What should I do next?










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    3














    I need to prove the following:



    Let $F:Bbb{R}toBbb{R}^2$ be the smooth map $F(t)=(cos t,sin t)$. Then $d/dtinmathcal{T}(Bbb{R})$ is $F$-related to the vector field $Zinmathcal{T}(Bbb{R}^2)$ defined by $$Z=xfrac{∂}{∂y}-yfrac{∂}{∂x}.$$



    So for any smooth $f$ defined on an open subset of $Bbb{R}^2$ we want $$frac{d}{dt}(fcirc F)=(xfrac{∂}{∂y}f-yfrac{∂}{∂x}f)circ F.$$ That is,$$frac{∂}{∂x}ffrac{d}{dt}F+frac{∂}{∂y}ffrac{d}{dt}F=(xfrac{∂}{∂y}f-yfrac{∂}{∂x}f)circ F.$$ What should I do next?










    share|cite|improve this question

























      3












      3








      3







      I need to prove the following:



      Let $F:Bbb{R}toBbb{R}^2$ be the smooth map $F(t)=(cos t,sin t)$. Then $d/dtinmathcal{T}(Bbb{R})$ is $F$-related to the vector field $Zinmathcal{T}(Bbb{R}^2)$ defined by $$Z=xfrac{∂}{∂y}-yfrac{∂}{∂x}.$$



      So for any smooth $f$ defined on an open subset of $Bbb{R}^2$ we want $$frac{d}{dt}(fcirc F)=(xfrac{∂}{∂y}f-yfrac{∂}{∂x}f)circ F.$$ That is,$$frac{∂}{∂x}ffrac{d}{dt}F+frac{∂}{∂y}ffrac{d}{dt}F=(xfrac{∂}{∂y}f-yfrac{∂}{∂x}f)circ F.$$ What should I do next?










      share|cite|improve this question













      I need to prove the following:



      Let $F:Bbb{R}toBbb{R}^2$ be the smooth map $F(t)=(cos t,sin t)$. Then $d/dtinmathcal{T}(Bbb{R})$ is $F$-related to the vector field $Zinmathcal{T}(Bbb{R}^2)$ defined by $$Z=xfrac{∂}{∂y}-yfrac{∂}{∂x}.$$



      So for any smooth $f$ defined on an open subset of $Bbb{R}^2$ we want $$frac{d}{dt}(fcirc F)=(xfrac{∂}{∂y}f-yfrac{∂}{∂x}f)circ F.$$ That is,$$frac{∂}{∂x}ffrac{d}{dt}F+frac{∂}{∂y}ffrac{d}{dt}F=(xfrac{∂}{∂y}f-yfrac{∂}{∂x}f)circ F.$$ What should I do next?







      differential-geometry differential-topology






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      asked Dec 8 '13 at 14:48









      figurafigura

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          LHS:
          $$frac{d}{dt}(fcirc F)= frac{d}{dt}(f(cos t, sin t))=f_x cdot (-sin t)+f_y cdot cos t$$



          RHS:
          $$(xfrac{∂}{∂y}f-yfrac{∂}{∂x}f)circ F= (xcirc F) f_x-(ycirc F) f_y= cos t cdot f_y - sin t cdot f_x$$



          So they are equal.






          share|cite|improve this answer























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            1 Answer
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            active

            oldest

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            1 Answer
            1






            active

            oldest

            votes









            active

            oldest

            votes






            active

            oldest

            votes









            3














            LHS:
            $$frac{d}{dt}(fcirc F)= frac{d}{dt}(f(cos t, sin t))=f_x cdot (-sin t)+f_y cdot cos t$$



            RHS:
            $$(xfrac{∂}{∂y}f-yfrac{∂}{∂x}f)circ F= (xcirc F) f_x-(ycirc F) f_y= cos t cdot f_y - sin t cdot f_x$$



            So they are equal.






            share|cite|improve this answer




























              3














              LHS:
              $$frac{d}{dt}(fcirc F)= frac{d}{dt}(f(cos t, sin t))=f_x cdot (-sin t)+f_y cdot cos t$$



              RHS:
              $$(xfrac{∂}{∂y}f-yfrac{∂}{∂x}f)circ F= (xcirc F) f_x-(ycirc F) f_y= cos t cdot f_y - sin t cdot f_x$$



              So they are equal.






              share|cite|improve this answer


























                3












                3








                3






                LHS:
                $$frac{d}{dt}(fcirc F)= frac{d}{dt}(f(cos t, sin t))=f_x cdot (-sin t)+f_y cdot cos t$$



                RHS:
                $$(xfrac{∂}{∂y}f-yfrac{∂}{∂x}f)circ F= (xcirc F) f_x-(ycirc F) f_y= cos t cdot f_y - sin t cdot f_x$$



                So they are equal.






                share|cite|improve this answer














                LHS:
                $$frac{d}{dt}(fcirc F)= frac{d}{dt}(f(cos t, sin t))=f_x cdot (-sin t)+f_y cdot cos t$$



                RHS:
                $$(xfrac{∂}{∂y}f-yfrac{∂}{∂x}f)circ F= (xcirc F) f_x-(ycirc F) f_y= cos t cdot f_y - sin t cdot f_x$$



                So they are equal.







                share|cite|improve this answer














                share|cite|improve this answer



                share|cite|improve this answer








                edited Nov 29 '18 at 14:24









                amWhy

                192k28225439




                192k28225439










                answered Apr 27 '14 at 19:42









                WWKWWK

                1,003722




                1,003722






























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