I have been trying to solve the following Korteweg-de Vries (KdV) equation using NDSolve but nothing went right!

\begin{align} 6 U_{t} + \frac{9}{2} U_{xxx} + 9 U U_{x} - 6 a U_{x} = 0\\ U_{xx} + \frac{9}{2} U^2-6a =0 \end{align}

with initial condition: \begin{align} U_{0}(x) = 2 a \sec^2\left(\sqrt{(3a/2)}x \right) \end{align}

and the boundary conditions are:

$$ U=U_{x}=U_{xx}=U_{xxx}=0 $$ as $x$ goes to $0$ and $a = 0.2$

  • 4
    $\begingroup$ Could you provide the actual Mathematic code you're using instead of the LaTeX format? Also in terms of LaTeX formatting you can use that directly here by putting it in $$ $\endgroup$ – b3m2a1 Feb 4 at 6:40
  • $\begingroup$ I just edited your formulas using „common sense“ (unfortuntely usually not helpful in Physics), please check. Also there is \begin{align} … \\ … end{align} for equations in MathJax. This tutorial on using MathJax will leave no question unanswered regarding LaTex in this environment. $\endgroup$ – gwr Feb 4 at 7:47
  • $\begingroup$ Thank you so much Sir. $\endgroup$ – Ali Joohy Feb 4 at 14:52
  • $\begingroup$ I fail to undrestand..how you can have two equations and one unknown? Am I missing somthing? $\endgroup$ – zhk Feb 10 at 15:42
  • $\begingroup$ These two equations refer to two separate questions, each main equations deeded to be solved along with the boundary and initial conditions, thanks $\endgroup$ – Ali Joohy Feb 13 at 7:28

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.