create an ellipse that is cut in half in matlab

To create an ellipse cut in half, you can use the patch function in MATLAB which allows us to create custom shapes. Here's an example code that creates an ellipse cut in half:

main.m
theta = linspace(pi/2,-pi/2,100);
x = 2*cos(theta);
y = sin(theta);
X = [x x(end) 0];
Y = [y -y(end) 0];
patch(X,Y,'b');
axis equal
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In the code above, we first create an array of theta values that range from pi/2 to -pi/2. We then define the x and y coordinates of the ellipse using these theta values. Finally, we set the x and y coordinates of the patch object such that it contains the coordinates of the upper half of the ellipse, the coordinates of the lower half of the ellipse (in reverse order) and a point at the origin to complete the shape. The 'b' argument sets the color of the patch to blue.

The axis equal command ensures that the x and y scales are the same, so that the ellipse appears circular.

This should give you an ellipse cut in half like this: