% When plotting a function in octave, I might want to plot axes so they meet
% at the coordinate origin, instead as boxes aroung the function graph.
% This might only make sense if the origin of the coordinate system is even
% contained within the plotted area.
x=linspace(-4,1);
plot(x,2*x+4,'r.',x,sqrt(2*x+4),'b.');
set(gca,'xaxislocation','origin'); % push x axis to the origin of the coordinate system
set(gca,'yaxislocation','origin'); % push y axis to the origin of the coordinate system
set(gca,'box','off');              % turn off the coordinate box around the graph.