A conic section, conic or a quadratic curve is a curve obtained from a cone's surface intersecting a plane. The three types of conic section are the hyperbola, the parabola, and the ellipse; the circle is a special case of the ellipse, though it was sometimes called as a fourth type. The ancient Greek mathematicians studied conic sections, culminating around 200 BC with Apollonius of Perga's systematic work on their properties.
This diagram clarifies the different angles of the cutting planes that result in the different properties of the three types of conic section.
Types of conic sections: 1: Circle 2: Ellipse 3: Parabola 4: Hyperbola
Diagram from Apollonius' Conics, in a 9th-century Arabic translation
Table of conics, Cyclopaedia, 1728
In mathematics, a curve is an object similar to a line, but that does not have to be straight.
Megalithic art from Newgrange showing an early interest in curves
A dragon curve with a positive area