Nonlinear differential equations, method












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There is a nonlinear differential equation $$ F(x, y, y',...,y^{(n)} )=0$$ One method to solve it is to use substitution $y'=yz$, but before that, there is one condition that has to be satisfied and that is $F(x, t_y, t_y',...,t_y^{(n)} )=t^{n}F(x, y, y',...,y^{(n)} )$. I found this in some notebooks, and I simply don't get what this $t$ represents.
Is anyone familiar with this method? I couldn't find anything on the internet, so I would be very grateful if somebody could explain this equality to me.



To be clearer, there is an example:
$$y(xy''+y')=xy'^2(1-x)$$
Checking the condition: $t_y (xt_y ''+t_y ')=xt^2y'^2(1-x)$



Substitution: $y'=yz$.










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    0












    $begingroup$


    There is a nonlinear differential equation $$ F(x, y, y',...,y^{(n)} )=0$$ One method to solve it is to use substitution $y'=yz$, but before that, there is one condition that has to be satisfied and that is $F(x, t_y, t_y',...,t_y^{(n)} )=t^{n}F(x, y, y',...,y^{(n)} )$. I found this in some notebooks, and I simply don't get what this $t$ represents.
    Is anyone familiar with this method? I couldn't find anything on the internet, so I would be very grateful if somebody could explain this equality to me.



    To be clearer, there is an example:
    $$y(xy''+y')=xy'^2(1-x)$$
    Checking the condition: $t_y (xt_y ''+t_y ')=xt^2y'^2(1-x)$



    Substitution: $y'=yz$.










    share|cite|improve this question









    $endgroup$















      0












      0








      0





      $begingroup$


      There is a nonlinear differential equation $$ F(x, y, y',...,y^{(n)} )=0$$ One method to solve it is to use substitution $y'=yz$, but before that, there is one condition that has to be satisfied and that is $F(x, t_y, t_y',...,t_y^{(n)} )=t^{n}F(x, y, y',...,y^{(n)} )$. I found this in some notebooks, and I simply don't get what this $t$ represents.
      Is anyone familiar with this method? I couldn't find anything on the internet, so I would be very grateful if somebody could explain this equality to me.



      To be clearer, there is an example:
      $$y(xy''+y')=xy'^2(1-x)$$
      Checking the condition: $t_y (xt_y ''+t_y ')=xt^2y'^2(1-x)$



      Substitution: $y'=yz$.










      share|cite|improve this question









      $endgroup$




      There is a nonlinear differential equation $$ F(x, y, y',...,y^{(n)} )=0$$ One method to solve it is to use substitution $y'=yz$, but before that, there is one condition that has to be satisfied and that is $F(x, t_y, t_y',...,t_y^{(n)} )=t^{n}F(x, y, y',...,y^{(n)} )$. I found this in some notebooks, and I simply don't get what this $t$ represents.
      Is anyone familiar with this method? I couldn't find anything on the internet, so I would be very grateful if somebody could explain this equality to me.



      To be clearer, there is an example:
      $$y(xy''+y')=xy'^2(1-x)$$
      Checking the condition: $t_y (xt_y ''+t_y ')=xt^2y'^2(1-x)$



      Substitution: $y'=yz$.







      ordinary-differential-equations






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      share|cite|improve this question











      share|cite|improve this question




      share|cite|improve this question










      asked Jan 6 at 17:20









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