Re: [Maxima-discuss] Fatal error

[Gunter K. <gu...@pe...>]

On 04.06.2018 18:37, Sergio Sanz Hernández via Maxima-discuss wrote:
> drawdf([y,-9*sin(x)-y/5], tstep=0.05,
>               soln_arrows=true, point_size=0.5,
>               points_at([0,0], [2*%pi,0], [-2*%pi,0]),
>               field_degree='solns,
>               saddles_at([%pi,0], [-%pi,0]));

My guess is that x and y are undefined unless you replace the

[y,-9*sin(x)-y/5]

by a

[y,-9*sin(x)-y/5], [x,-10,10], [y,-10,10]

Kind regards,

 Gunter.