Let $y' = g(t,y)sin^2(y)$, discuting limit of solution.












1












$begingroup$


Let $y' = g(t,y)sin^2(y)$, with $ g: mathbb{R} times mathbb{R}to mathbb{R}$, g differentiable.



I want to prove that if a solution is maximal, there exists the limits $lim_{tto pm infty} y(t)$.



This is what I have done: product of differentiable functions is still differentiable, so I can say that there exists a local solution and it is unique.Then there also exists a maximal solution that is unique.



To try and calculate that limit I must also say that the maximal solutions are globally defined on all $mathbb{R}$, which is where I am stuck. Besides, even assuming that I know this fact, I would not know how to continue.



Any hint?










share|cite|improve this question









$endgroup$

















    1












    $begingroup$


    Let $y' = g(t,y)sin^2(y)$, with $ g: mathbb{R} times mathbb{R}to mathbb{R}$, g differentiable.



    I want to prove that if a solution is maximal, there exists the limits $lim_{tto pm infty} y(t)$.



    This is what I have done: product of differentiable functions is still differentiable, so I can say that there exists a local solution and it is unique.Then there also exists a maximal solution that is unique.



    To try and calculate that limit I must also say that the maximal solutions are globally defined on all $mathbb{R}$, which is where I am stuck. Besides, even assuming that I know this fact, I would not know how to continue.



    Any hint?










    share|cite|improve this question









    $endgroup$















      1












      1








      1





      $begingroup$


      Let $y' = g(t,y)sin^2(y)$, with $ g: mathbb{R} times mathbb{R}to mathbb{R}$, g differentiable.



      I want to prove that if a solution is maximal, there exists the limits $lim_{tto pm infty} y(t)$.



      This is what I have done: product of differentiable functions is still differentiable, so I can say that there exists a local solution and it is unique.Then there also exists a maximal solution that is unique.



      To try and calculate that limit I must also say that the maximal solutions are globally defined on all $mathbb{R}$, which is where I am stuck. Besides, even assuming that I know this fact, I would not know how to continue.



      Any hint?










      share|cite|improve this question









      $endgroup$




      Let $y' = g(t,y)sin^2(y)$, with $ g: mathbb{R} times mathbb{R}to mathbb{R}$, g differentiable.



      I want to prove that if a solution is maximal, there exists the limits $lim_{tto pm infty} y(t)$.



      This is what I have done: product of differentiable functions is still differentiable, so I can say that there exists a local solution and it is unique.Then there also exists a maximal solution that is unique.



      To try and calculate that limit I must also say that the maximal solutions are globally defined on all $mathbb{R}$, which is where I am stuck. Besides, even assuming that I know this fact, I would not know how to continue.



      Any hint?







      ordinary-differential-equations initial-value-problems






      share|cite|improve this question













      share|cite|improve this question











      share|cite|improve this question




      share|cite|improve this question










      asked Jan 12 at 15:40









      qcc101qcc101

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