Transforming Bessel's equation with change of variables












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$begingroup$


Let bessel's equation be written as



$ z^2$$frac{d^2w}{dz^2}$ + $z$$frac{dw}{dz}$ + $(z^2 -p^2)w$ = $0$



and show that the change of variables defined by $z = ax^b$ and $w = yx^c$ (where a,b and c are constants) transforms it into



$ x^2$$frac{d^2y}{dx^2}$ + $(2c+1)xfrac {dy}{dx}$ + $[a^2b^2(x)^{2b} + (c^2 - p^2b^2)]y$ = $0$



Write the general solution of this equation in terms of Bessels function.



I also don't understand why we use this transformation. Any help would be apreciated.










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$endgroup$

















    0












    $begingroup$


    Let bessel's equation be written as



    $ z^2$$frac{d^2w}{dz^2}$ + $z$$frac{dw}{dz}$ + $(z^2 -p^2)w$ = $0$



    and show that the change of variables defined by $z = ax^b$ and $w = yx^c$ (where a,b and c are constants) transforms it into



    $ x^2$$frac{d^2y}{dx^2}$ + $(2c+1)xfrac {dy}{dx}$ + $[a^2b^2(x)^{2b} + (c^2 - p^2b^2)]y$ = $0$



    Write the general solution of this equation in terms of Bessels function.



    I also don't understand why we use this transformation. Any help would be apreciated.










    share|cite|improve this question









    $endgroup$















      0












      0








      0





      $begingroup$


      Let bessel's equation be written as



      $ z^2$$frac{d^2w}{dz^2}$ + $z$$frac{dw}{dz}$ + $(z^2 -p^2)w$ = $0$



      and show that the change of variables defined by $z = ax^b$ and $w = yx^c$ (where a,b and c are constants) transforms it into



      $ x^2$$frac{d^2y}{dx^2}$ + $(2c+1)xfrac {dy}{dx}$ + $[a^2b^2(x)^{2b} + (c^2 - p^2b^2)]y$ = $0$



      Write the general solution of this equation in terms of Bessels function.



      I also don't understand why we use this transformation. Any help would be apreciated.










      share|cite|improve this question









      $endgroup$




      Let bessel's equation be written as



      $ z^2$$frac{d^2w}{dz^2}$ + $z$$frac{dw}{dz}$ + $(z^2 -p^2)w$ = $0$



      and show that the change of variables defined by $z = ax^b$ and $w = yx^c$ (where a,b and c are constants) transforms it into



      $ x^2$$frac{d^2y}{dx^2}$ + $(2c+1)xfrac {dy}{dx}$ + $[a^2b^2(x)^{2b} + (c^2 - p^2b^2)]y$ = $0$



      Write the general solution of this equation in terms of Bessels function.



      I also don't understand why we use this transformation. Any help would be apreciated.







      ordinary-differential-equations bessel-functions






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      asked Oct 17 '16 at 14:37









      user34304user34304

      1,27911230




      1,27911230






















          2 Answers
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          0












          $begingroup$

          It is because you are invited to chose $b$ and $c$ such that the constant $c^2 - p^2b^2$ is equal to $0$. In this way you obtain a simpler differential equation...






          share|cite|improve this answer









          $endgroup$













          • $begingroup$
            But how would you accomplish that?
            $endgroup$
            – user34304
            Oct 17 '16 at 15:21



















          0












          $begingroup$

          It is because the solution of the FIRST equation can be written as c1*F(z)+c2*G(z), where c1, c2 are computed based on the boundary conditions and F, G are Bessel functions.



          Therefore, any equation that follows the SECOND equation pattern can be tranformed into an equivalent first equation, and thus be easily solved.






          share|cite|improve this answer









          $endgroup$













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            2 Answers
            2






            active

            oldest

            votes








            2 Answers
            2






            active

            oldest

            votes









            active

            oldest

            votes






            active

            oldest

            votes









            0












            $begingroup$

            It is because you are invited to chose $b$ and $c$ such that the constant $c^2 - p^2b^2$ is equal to $0$. In this way you obtain a simpler differential equation...






            share|cite|improve this answer









            $endgroup$













            • $begingroup$
              But how would you accomplish that?
              $endgroup$
              – user34304
              Oct 17 '16 at 15:21
















            0












            $begingroup$

            It is because you are invited to chose $b$ and $c$ such that the constant $c^2 - p^2b^2$ is equal to $0$. In this way you obtain a simpler differential equation...






            share|cite|improve this answer









            $endgroup$













            • $begingroup$
              But how would you accomplish that?
              $endgroup$
              – user34304
              Oct 17 '16 at 15:21














            0












            0








            0





            $begingroup$

            It is because you are invited to chose $b$ and $c$ such that the constant $c^2 - p^2b^2$ is equal to $0$. In this way you obtain a simpler differential equation...






            share|cite|improve this answer









            $endgroup$



            It is because you are invited to chose $b$ and $c$ such that the constant $c^2 - p^2b^2$ is equal to $0$. In this way you obtain a simpler differential equation...







            share|cite|improve this answer












            share|cite|improve this answer



            share|cite|improve this answer










            answered Oct 17 '16 at 14:54









            Jean MarieJean Marie

            29.3k42050




            29.3k42050












            • $begingroup$
              But how would you accomplish that?
              $endgroup$
              – user34304
              Oct 17 '16 at 15:21


















            • $begingroup$
              But how would you accomplish that?
              $endgroup$
              – user34304
              Oct 17 '16 at 15:21
















            $begingroup$
            But how would you accomplish that?
            $endgroup$
            – user34304
            Oct 17 '16 at 15:21




            $begingroup$
            But how would you accomplish that?
            $endgroup$
            – user34304
            Oct 17 '16 at 15:21











            0












            $begingroup$

            It is because the solution of the FIRST equation can be written as c1*F(z)+c2*G(z), where c1, c2 are computed based on the boundary conditions and F, G are Bessel functions.



            Therefore, any equation that follows the SECOND equation pattern can be tranformed into an equivalent first equation, and thus be easily solved.






            share|cite|improve this answer









            $endgroup$


















              0












              $begingroup$

              It is because the solution of the FIRST equation can be written as c1*F(z)+c2*G(z), where c1, c2 are computed based on the boundary conditions and F, G are Bessel functions.



              Therefore, any equation that follows the SECOND equation pattern can be tranformed into an equivalent first equation, and thus be easily solved.






              share|cite|improve this answer









              $endgroup$
















                0












                0








                0





                $begingroup$

                It is because the solution of the FIRST equation can be written as c1*F(z)+c2*G(z), where c1, c2 are computed based on the boundary conditions and F, G are Bessel functions.



                Therefore, any equation that follows the SECOND equation pattern can be tranformed into an equivalent first equation, and thus be easily solved.






                share|cite|improve this answer









                $endgroup$



                It is because the solution of the FIRST equation can be written as c1*F(z)+c2*G(z), where c1, c2 are computed based on the boundary conditions and F, G are Bessel functions.



                Therefore, any equation that follows the SECOND equation pattern can be tranformed into an equivalent first equation, and thus be easily solved.







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered Nov 9 '17 at 3:57









                Michael NikolaouMichael Nikolaou

                112




                112






























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