MathGroup Archive 2009

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: Is this solvable using Mathematica?


One problem is that d doesn't have a value...

On Apr 25, 10:49 am, johnboy98... at yahoo.com wrote:
> Supposed you want to define a second order derivative along with your
> ODEs. (So you can scale the second order term)
>
> Example shown below.
>
> k1 = 1;
> r1 = 1;
> NDSolve[{a'[t] == k1 b[t] - d, a''[t] == r1 b'[t], a'[0] == 0=
, a[0] ==
> 1, b[0] == 0}, {a[t], b[t]}, {t, 1, 10} ]
>
> But I get an error.
>
> NDSolve::ntdvmm:
> Cannot solve to find an explicit formula for the derivatives.  NDSolve
> will try solving the system using a mass matrix method.
>
> NDSolve::ndnum: Encountered non-numerical value for a derivative at t
> == 0.`.
>
> Maybe this is more of a math question than software. But I would be
> very interested in seeing if it's doable in Mathematica.
>
> Thanks in advance.



  • Prev by Date: Re: Replace elements in structured list
  • Next by Date: Re: ContourPlot, equation and R.H. side of equation_Plotting problem
  • Previous by thread: Is this solvable using Mathematica?
  • Next by thread: Re: Is this solvable using Mathematica?