It seems that Maxima introduces new variable %u as a parameter.
Try the following code which passes the computation directly to maxima:
%maxima
load(contrib_ode);
eq:'diff(x,t)-x*(1-x)+a*(1+sin(2*pi*t))=0;
contrib_ode(eq,x,t);
I got:
[[x='diff(%u,t,1)/%u,%u*(-a*sin(2*pi*t)-a)-'diff(%u,t,2)+'diff(%u,t,1)=0]]
These new variables are always problem in Sage, since these variables are
not declared by var command. I think, that there is a ticket on trac with
this problem, which appears also when solving some equations.
The code which is responsible for solving Riccati ode is in the file
ode1_riccati.mac in the sources of Maxima.
Hope this helps
Robert
Dne pátek, 12. října 2012 0:37:50 UTC+2 Doaa El-Sakout napsal(a):
>
> I try to solve an ODE and plot the result as follows,
>
>
> x,t,a=var('x,t,a')
> a=0.29
> x = function('x', t)
> S=desolve(diff(x,t)-x*(1-x)+a*
> (1+sin(2*pi*t)),x,contrib_ode=True,show_method=True)
> S
>
> I found the following
> [[[x(t) == 0, (-0.29*sin(2*pi*t) - 0.29)*u == 0]], 'riccati']
>
> So what is this "u" here and how can I plot this and how the solution
> wrote by this way
> it is not clear what does it mean
> Doaa
>
>
>
>
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