# plotting an open circle (open interval) in plot

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cgo on 27 May 2020
Answered: Image Analyst on 27 May 2020
i am plotting a function f =@(x) x.^2 but i want to put open circles at x = 0 and x = 4 because they are undefined at those points. How do i put the open circles?
I am using fplot(f, [0,2])

darova on 27 May 2020
Can you make a simple sketch? How do you want it to look?
cgo on 27 May 2020
See the small circle there? I want it to be larger. (or is there an easier way to do this) because I am graphing an open interval, so it is 'not defined' at y = 4, hence the open/unshaded circle. darova on 27 May 2020
Use markerSize property
plot(x(end),y(end),'ob','markersize',20)

Image Analyst on 27 May 2020
Try this:
% Create data.
x = linspace(0, 4, 1000);
y = x .^ 2;
plot(x, y, 'b-', 'LineWidth', 2); % Plot line.
hold on; % Don't let circles blow away the line.
plot([x(1), x(end)], [y(1), y(end)], 'ro', 'MarkerSize', 15, 'LineWidth', 2);
grid on;
xlabel('X', 'FontSize', 15);
ylabel('Y', 'FontSize', 15); Adjust MarkerSize and LineWidth as desired.