See https://en.wikipedia.org/wiki/Ellipse#Directrixsymbolipoint said:I do not understand this: An ellipse has a directrix?
A parabola, for sure. This is part of the definition and we can derive the equation of a parabola using the meaning of Directrix and the meaning of Parabola. How does a directrix work for an ellipse?
The directrix is a line or curve that is used to construct a geometric figure, such as a parabola. It is an important element in conic sections and is essential in defining the shape and position of the curve.
Yes, a directrix can be used for curves other than a parabola. In fact, it is a fundamental concept in conic sections and can be used to construct other curves such as ellipses and hyperbolas.
The directrix and focus are two key components of a conic section. The directrix is a fixed line or curve that is used to create the curve, while the focus is a fixed point that determines the shape and position of the curve in relation to the directrix.
The concept of the directrix has many practical applications in fields such as architecture, engineering, and physics. For example, in architecture, the concept of a directrix is used in designing curved structures such as arches and domes.
The equation of a directrix depends on the type of curve being constructed. For a parabola, the equation of the directrix can be found by using the vertex and focus of the parabola. For other curves, such as ellipses and hyperbolas, different methods may be used to determine the equation of the directrix.