**Quadratic Curves ( Conics )**

There are the curve which appears when cone
is cut in the plane which doesn't contain
a vertex with rigth circular cone.

We knows these conics by names found in Apollonius
(BC 247?-205?).

Ellipse

Hyperbola

Parabola

Famous Theorems in Plane Geometry

When it was the 19th century, the geometrical
nature of Conics was researched as the development
of projective geometry.The followings are
intimate relations of conics.

Simson

Brianchon

Pascal