21. Write a user-defined function that plots an ellipse with axes that are parallel to the x and y axes, given the coordinates of its vertices and the coordinates of another point that the ellipse passes through. For the function name and arguments, use ellipseplot(A,B,C). The input arguments A and B are each a two-element vector with the coordinates of the vertices, and C is a two-element vector with the coordinates of another point on the ellipse (see figure), respectively.

This function has no output arguments. Use the function to plot the following ellipses:

(a) A(2,3), B(11,3), C(10,4)

(b) A(2,11), B(2,–4), C(4,8)