f(x,y)<=0

How can I plot the Domain of f(x,y)<=0 in Oxy?

Can someone give me advices?

Thanks.

Answer 1

[John D'Errico]

I can see several ways off the top of my head.

Consider some arbitrary implicit function.

fun = @(x,y) x.^2 + y.^3 - 3;

Easy enough to plot the region boundary, so the locus of where it equals zero.

fimplicit(fun,[-4,4],-3,2])
grid

But which half of that domain is the negative part? pcolor should work.

[X,Y] = meshgrid(linspace(-4,4,500),linspace(-3,2,500));
Fxy = fun(X,Y);
H = pcolor(X,Y,double(Fxy < 0);
H.EdgeColor = 'none';
colormap([1 1 1;.1 .6 .7])