Update: I tried it again differently
if true
[T, Y]=meshgrid(-5:0.1:5,-5:0.1:5);
dY=Y*(r-exp(x));
dT=ones(size(dY));
L=sqrt(1+dY.^2);
quiver(T, Y, dT./L, dY./L, 0.5)
axis tight
end
and even if I replace r with 1, 0 and -1 (just for trying out reasons) it doesn't work. So I'm guessing I need to define r differently?
Greetings