Re: [Maxima-discuss] Problem with draw2d(implicit(...))

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

On 22.03.20 21:41, Richard Fateman wrote:
> This is probably not going to solve this particular problem,
> but the general problem of making sure that plots don't lie
> because of numerical errors can be addressed by interval
> arithmetic, at least sometimes.   google search for "honest plotting".
> Not that Maxima has any seriously implemented interval arithmetic.
> RJF
>
Interval arithmetic is easy to implement for anything which is both
continuous and monotonous - and can be extended to such functions with
more than input (for example multiplications). For machine-float
periodic functions like sin(x) and tan(x) we could perhaps get info
about the periodicity for large x.

The question is if this is enough for this case or if we would need an
interval arithmetics for find_root - which is impossible for more than
trivial problems.