Parabolic Mirror, Theory

Parabola is a conic defined by its focal property: there is a point - focus - and a line - directrix - and parabola is the locus of points equidistant from the focus and the directrix.

It is known that the tangent to parabola at a point bisects the angle between the segments joining the point to the focus and the directrix.

This is equivalent to saying that, if a light source is located at the focus, the rays from the source reflected in the inner surface of the parabolic mirror are parallel. What good is this property? Well, this is how modern car lights work. And this is the principle underlying radio telescopy.

Conic Sections > Parabola

The Parabola
Archimedes Triangle and Squaring of Parabola
Focal Definition of Parabola
Focal Properties of Parabola
Geometric Construction of Roots of Quadratic Equation
Given Parabola, Find Axis
Graph and Roots of Quadratic Polynomial
Greg Markowsky's Problem for Parabola
Parabola As Envelope of Straight Lines
Generation of parabola via Apollonius' mesh
Parabolic Mirror, Theory
Parabolic Mirror, Illustration
Three Parabola Tangents
Three Points on a Parabola
Two Tangents to Parabola
Parabolic Sieve of Prime Numbers
Parabolic Reciprocity
Parabolas Related to the Orthic Triangle

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