A given is a rectangle ABCD with the corners 
, and 
.
Obtain the equation of the ellipse in the central position, which is plotted in the rectangle ABCD and touches all four of his sides.
Obtain the equation of a hyperbola in the central position, which has vertices at 
and its asymptotes. They are the diagonals of the rectangle ABCD.
Obtain the equation of a circle that has its center at the point C and passes through the point A.
