A parabola is a curve that looks like the one on the right. Its open end can point up, down, left or right.
A curve of this shape is called 'parabolic', meaning 'like a parabola'.
There are three common ways to define a parabola:
1. Focus and Directrix
In this definition we start with a line (directrix) and a point (focus) and plot the
of all points
equidistant from each.
For more see
Parabola (focus and directrix).
2. The graph of a function
When we plot the graph of a function of the form
the x2 term causes it to be in the shape of a parabola.
For more on this see
Parabola (Graph of a function).
3. As a conic section
A parabola is formed at the intersection of a plane and a cone when the plane is parallel to one side of the cone.
See Parabola (Conic section).
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