Can't plot DSolve's solution to Riccati differential equation











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DSolve gives a strange solution for the Riccati differential equation $ y' = (y^2) - 2 x^2 y + (x^4) + 2 x + 4 $



Opres = DSolve[y'[x] == y[x]^2-2x^2*y[x]+x^4+2x+4, y[x], x]


$left{left{y(x)to frac{1}{c_1 e^{4 i x}-frac{i}{4}}+x^2-2 iright}right}$



When I try plot this solution



Opresgraf = 
Plot[Evaluate[y[x] /. Opres /. C[1] -> Range[-3, 3]], {x, -4.7, 4.7},
PlotRange -> 4.7]


I get a blank graph.



My question is: how can I get a solution with DSolve (not with NDSolve, because in my student research project I need DSolve) and plot that solution, the most important is to plot that general solution with DSolve.










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  • 1




    You can't plot a complex expression. You need to either plot its real value, its imaginary value or its modulus. Also you have a typo in the input, you need y[x] not y in the ODE itself.
    – Nasser
    4 hours ago






  • 1




    Is Range[-3.3] supposed to be Range[-3,3]?
    – That Gravity Guy
    4 hours ago















up vote
2
down vote

favorite












DSolve gives a strange solution for the Riccati differential equation $ y' = (y^2) - 2 x^2 y + (x^4) + 2 x + 4 $



Opres = DSolve[y'[x] == y[x]^2-2x^2*y[x]+x^4+2x+4, y[x], x]


$left{left{y(x)to frac{1}{c_1 e^{4 i x}-frac{i}{4}}+x^2-2 iright}right}$



When I try plot this solution



Opresgraf = 
Plot[Evaluate[y[x] /. Opres /. C[1] -> Range[-3, 3]], {x, -4.7, 4.7},
PlotRange -> 4.7]


I get a blank graph.



My question is: how can I get a solution with DSolve (not with NDSolve, because in my student research project I need DSolve) and plot that solution, the most important is to plot that general solution with DSolve.










share|improve this question




















  • 1




    You can't plot a complex expression. You need to either plot its real value, its imaginary value or its modulus. Also you have a typo in the input, you need y[x] not y in the ODE itself.
    – Nasser
    4 hours ago






  • 1




    Is Range[-3.3] supposed to be Range[-3,3]?
    – That Gravity Guy
    4 hours ago













up vote
2
down vote

favorite









up vote
2
down vote

favorite











DSolve gives a strange solution for the Riccati differential equation $ y' = (y^2) - 2 x^2 y + (x^4) + 2 x + 4 $



Opres = DSolve[y'[x] == y[x]^2-2x^2*y[x]+x^4+2x+4, y[x], x]


$left{left{y(x)to frac{1}{c_1 e^{4 i x}-frac{i}{4}}+x^2-2 iright}right}$



When I try plot this solution



Opresgraf = 
Plot[Evaluate[y[x] /. Opres /. C[1] -> Range[-3, 3]], {x, -4.7, 4.7},
PlotRange -> 4.7]


I get a blank graph.



My question is: how can I get a solution with DSolve (not with NDSolve, because in my student research project I need DSolve) and plot that solution, the most important is to plot that general solution with DSolve.










share|improve this question















DSolve gives a strange solution for the Riccati differential equation $ y' = (y^2) - 2 x^2 y + (x^4) + 2 x + 4 $



Opres = DSolve[y'[x] == y[x]^2-2x^2*y[x]+x^4+2x+4, y[x], x]


$left{left{y(x)to frac{1}{c_1 e^{4 i x}-frac{i}{4}}+x^2-2 iright}right}$



When I try plot this solution



Opresgraf = 
Plot[Evaluate[y[x] /. Opres /. C[1] -> Range[-3, 3]], {x, -4.7, 4.7},
PlotRange -> 4.7]


I get a blank graph.



My question is: how can I get a solution with DSolve (not with NDSolve, because in my student research project I need DSolve) and plot that solution, the most important is to plot that general solution with DSolve.







differential-equations






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edited 28 secs ago









kglr

173k8194400




173k8194400










asked 4 hours ago









Милош Вучковић

415




415








  • 1




    You can't plot a complex expression. You need to either plot its real value, its imaginary value or its modulus. Also you have a typo in the input, you need y[x] not y in the ODE itself.
    – Nasser
    4 hours ago






  • 1




    Is Range[-3.3] supposed to be Range[-3,3]?
    – That Gravity Guy
    4 hours ago














  • 1




    You can't plot a complex expression. You need to either plot its real value, its imaginary value or its modulus. Also you have a typo in the input, you need y[x] not y in the ODE itself.
    – Nasser
    4 hours ago






  • 1




    Is Range[-3.3] supposed to be Range[-3,3]?
    – That Gravity Guy
    4 hours ago








1




1




You can't plot a complex expression. You need to either plot its real value, its imaginary value or its modulus. Also you have a typo in the input, you need y[x] not y in the ODE itself.
– Nasser
4 hours ago




You can't plot a complex expression. You need to either plot its real value, its imaginary value or its modulus. Also you have a typo in the input, you need y[x] not y in the ODE itself.
– Nasser
4 hours ago




1




1




Is Range[-3.3] supposed to be Range[-3,3]?
– That Gravity Guy
4 hours ago




Is Range[-3.3] supposed to be Range[-3,3]?
– That Gravity Guy
4 hours ago










3 Answers
3






active

oldest

votes

















up vote
5
down vote













perhaps



Plot[Evaluate[ReIm@y[x] /. (Opres /. C[1] -> Range[-3, 3])], {x, -4.7, 4.7}, 
PlotRange -> 4.7]


enter image description here






share|improve this answer




























    up vote
    2
    down vote













    Try this



    Opres = DSolve[y'[x] == y[x]^2-2x^2 *y[x]+x^4+2x+4, y[x], x][[1]];
    Plot[{Re[y[x]/.Opres/.C[1]->Range[3.3]],Im[y[x]/.Opres/.C[1]->Range[3.3]]}, {x,-4.7,4.7}]





    share|improve this answer




























      up vote
      2
      down vote













      With a single graph you can only plot those solution that are imaginary or real.



      There are 2 real ones:



      sol = First[DSolve[y'[x] == y[x]^2 - 2 x^2*y[x] + x^4 + 2 x + 4, y[x], x]];
      zeroIm = FullSimplify[ComplexExpand[Im[y[x] /. sol]]] == 0 // Solve[#, C[1]] &



      $left{left{C[1]to -frac{1}{4}right},left{C[1]to frac{1}{4}right}right}$




      Plot[Evaluate[y[x] /. sol /. zeroIm], {x, -4.7, 4.7}]







      share|improve this answer























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        3 Answers
        3






        active

        oldest

        votes








        3 Answers
        3






        active

        oldest

        votes









        active

        oldest

        votes






        active

        oldest

        votes








        up vote
        5
        down vote













        perhaps



        Plot[Evaluate[ReIm@y[x] /. (Opres /. C[1] -> Range[-3, 3])], {x, -4.7, 4.7}, 
        PlotRange -> 4.7]


        enter image description here






        share|improve this answer

























          up vote
          5
          down vote













          perhaps



          Plot[Evaluate[ReIm@y[x] /. (Opres /. C[1] -> Range[-3, 3])], {x, -4.7, 4.7}, 
          PlotRange -> 4.7]


          enter image description here






          share|improve this answer























            up vote
            5
            down vote










            up vote
            5
            down vote









            perhaps



            Plot[Evaluate[ReIm@y[x] /. (Opres /. C[1] -> Range[-3, 3])], {x, -4.7, 4.7}, 
            PlotRange -> 4.7]


            enter image description here






            share|improve this answer












            perhaps



            Plot[Evaluate[ReIm@y[x] /. (Opres /. C[1] -> Range[-3, 3])], {x, -4.7, 4.7}, 
            PlotRange -> 4.7]


            enter image description here







            share|improve this answer












            share|improve this answer



            share|improve this answer










            answered 4 hours ago









            kglr

            173k8194400




            173k8194400






















                up vote
                2
                down vote













                Try this



                Opres = DSolve[y'[x] == y[x]^2-2x^2 *y[x]+x^4+2x+4, y[x], x][[1]];
                Plot[{Re[y[x]/.Opres/.C[1]->Range[3.3]],Im[y[x]/.Opres/.C[1]->Range[3.3]]}, {x,-4.7,4.7}]





                share|improve this answer

























                  up vote
                  2
                  down vote













                  Try this



                  Opres = DSolve[y'[x] == y[x]^2-2x^2 *y[x]+x^4+2x+4, y[x], x][[1]];
                  Plot[{Re[y[x]/.Opres/.C[1]->Range[3.3]],Im[y[x]/.Opres/.C[1]->Range[3.3]]}, {x,-4.7,4.7}]





                  share|improve this answer























                    up vote
                    2
                    down vote










                    up vote
                    2
                    down vote









                    Try this



                    Opres = DSolve[y'[x] == y[x]^2-2x^2 *y[x]+x^4+2x+4, y[x], x][[1]];
                    Plot[{Re[y[x]/.Opres/.C[1]->Range[3.3]],Im[y[x]/.Opres/.C[1]->Range[3.3]]}, {x,-4.7,4.7}]





                    share|improve this answer












                    Try this



                    Opres = DSolve[y'[x] == y[x]^2-2x^2 *y[x]+x^4+2x+4, y[x], x][[1]];
                    Plot[{Re[y[x]/.Opres/.C[1]->Range[3.3]],Im[y[x]/.Opres/.C[1]->Range[3.3]]}, {x,-4.7,4.7}]






                    share|improve this answer












                    share|improve this answer



                    share|improve this answer










                    answered 4 hours ago









                    Bill

                    5,41059




                    5,41059






















                        up vote
                        2
                        down vote













                        With a single graph you can only plot those solution that are imaginary or real.



                        There are 2 real ones:



                        sol = First[DSolve[y'[x] == y[x]^2 - 2 x^2*y[x] + x^4 + 2 x + 4, y[x], x]];
                        zeroIm = FullSimplify[ComplexExpand[Im[y[x] /. sol]]] == 0 // Solve[#, C[1]] &



                        $left{left{C[1]to -frac{1}{4}right},left{C[1]to frac{1}{4}right}right}$




                        Plot[Evaluate[y[x] /. sol /. zeroIm], {x, -4.7, 4.7}]







                        share|improve this answer



























                          up vote
                          2
                          down vote













                          With a single graph you can only plot those solution that are imaginary or real.



                          There are 2 real ones:



                          sol = First[DSolve[y'[x] == y[x]^2 - 2 x^2*y[x] + x^4 + 2 x + 4, y[x], x]];
                          zeroIm = FullSimplify[ComplexExpand[Im[y[x] /. sol]]] == 0 // Solve[#, C[1]] &



                          $left{left{C[1]to -frac{1}{4}right},left{C[1]to frac{1}{4}right}right}$




                          Plot[Evaluate[y[x] /. sol /. zeroIm], {x, -4.7, 4.7}]







                          share|improve this answer

























                            up vote
                            2
                            down vote










                            up vote
                            2
                            down vote









                            With a single graph you can only plot those solution that are imaginary or real.



                            There are 2 real ones:



                            sol = First[DSolve[y'[x] == y[x]^2 - 2 x^2*y[x] + x^4 + 2 x + 4, y[x], x]];
                            zeroIm = FullSimplify[ComplexExpand[Im[y[x] /. sol]]] == 0 // Solve[#, C[1]] &



                            $left{left{C[1]to -frac{1}{4}right},left{C[1]to frac{1}{4}right}right}$




                            Plot[Evaluate[y[x] /. sol /. zeroIm], {x, -4.7, 4.7}]







                            share|improve this answer














                            With a single graph you can only plot those solution that are imaginary or real.



                            There are 2 real ones:



                            sol = First[DSolve[y'[x] == y[x]^2 - 2 x^2*y[x] + x^4 + 2 x + 4, y[x], x]];
                            zeroIm = FullSimplify[ComplexExpand[Im[y[x] /. sol]]] == 0 // Solve[#, C[1]] &



                            $left{left{C[1]to -frac{1}{4}right},left{C[1]to frac{1}{4}right}right}$




                            Plot[Evaluate[y[x] /. sol /. zeroIm], {x, -4.7, 4.7}]








                            share|improve this answer














                            share|improve this answer



                            share|improve this answer








                            edited 3 hours ago

























                            answered 4 hours ago









                            Coolwater

                            14.3k32452




                            14.3k32452






























                                 

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