2 Connect the AC, and find a D on the AC.
3 make DC equal to 1/2 major axis-1/2 minor axis.
4 perpendicular bisector is AD.
5 and the long axis intersect at O 1, and then make the point O 1 a symmetrical point O2.
6 intersect with the minor axis O3, and then make the point O3 a symmetrical point O4.
7 Draw an arc with O3 and O4 as the center and O3E and O4D as the radius.
8 Draw an arc with O 1 as the center and O 1A as the radius.
9 Draw an arc with O2 as the center and O2B as the radius.
An ellipse is the trajectory of a moving point P. The sum of the distances from the moving point P to the fixed points F 1 and F2 in a plane is equal to a constant (greater than |F 1F2|), and F1and F2 are called the two focuses of the ellipse. The mathematical expression is | pf1|+pf2 | = 2a (2a > | f1F2 |).
An ellipse is a conic curve, that is, the tangent of a cone to a plane.