Circle As Limiting Case of Other Figures
The circle can be viewed as a limiting case of each of various other figures:
- A Cartesian oval is a set of points such that a weighted sum of the distances from any of its points to two fixed points (foci) is a constant. An ellipse is the case in which the weights are equal. A circle is an ellipse with an eccentricity of zero, meaning that the two foci coincide with each other as the centre of the circle. A circle is also a different special case of a Cartesian oval in which one of the weights is zero.
- A superellipse has an equation of the form for positive a, b, and n. A supercircle has b = a. A circle is the special case of a supercircle in which n = 2.
- A Cassini oval is a set of points such that the product of the distances from any of its points to two fixed points is a constant. When the two fixed points coincide, a circle results.
- A curve of constant width is a figure whose width, defined as the perpendicular distance between two distinct parallel lines each intersecting its boundary in a single point, is the same regardless of the direction of those two parallel lines. The circle is the simplest example of this type of figure.
Read more about this topic: Circle
Famous quotes containing the words circle, limiting, case and/or figures:
“A circle swoop, and a quick parabola under the bridge arches
Where light pushes through;
A sudden turning upon itself of a thing in the air.
A dip to the water.”
—D.H. (David Herbert)
“A way of certifying experience, taking photographs is also a way of refusing it—by limiting experience to a search for the photogenic, by converting experience into an image, a souvenir. Travel becomes a strategy for accumulating photographs.”
—Susan Sontag (b. 1933)
“Thought is an infection. In the case of certain thoughts, it becomes an epidemic.”
—Wallace Stevens (1879–1955)
“She, while her lover pants upon her breast,
Can mark the figures on an Indian chest.”
—Alexander Pope (1688–1744)