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An ellipse (red) obtained as the intersection of a cone with an inclined plane. Ellipse: notations Ellipses: examples with increasing eccentricity. In mathematics, an ellipse is a plane curve surrounding two focal points, such that for all points on the curve, the sum of the two distances to the focal points is a constant.
Elliptic coordinate system. In geometry, the elliptic coordinate system is a two-dimensional orthogonal coordinate system in which the coordinate lines are confocal ellipses and hyperbolae.
For example, on a triaxial ellipsoid, the meridional eccentricity is that of the ellipse formed by a section containing both the longest and the shortest axes (one of which will be the polar axis), and the equatorial eccentricity is the eccentricity of the ellipse formed by a section through the centre, perpendicular to the polar axis (i.e. in ...
Hence, it is confocal to the given ellipse and the length of the string is l = 2r x + (a − c). Solving for r x yields r x = 1 / 2 (l − a + c); furthermore r 2 y = r 2 x − c 2. From the upper diagram we see that S 1 and S 2 are the foci of the ellipse section of the ellipsoid in the xz-plane and that r 2 z = r 2 x − a 2.
Flattening is a measure of the compression of a circle or sphere along a diameter to form an ellipse or an ellipsoid of revolution respectively. Other terms used are ellipticity , or oblateness . The usual notation for flattening is f {\displaystyle f} and its definition in terms of the semi-axes a {\displaystyle a} and b {\displaystyle b} of ...
Elliptical distributions are defined in terms of the characteristic function of probability theory. A random vector X {\displaystyle X} on a Euclidean space has an elliptical distribution if its characteristic function ϕ {\displaystyle \phi } satisfies the following functional equation (for every column-vector t {\displaystyle t} )
In geometry, the n-ellipse is a generalization of the ellipse allowing more than two foci. [1] n-ellipses go by numerous other names, including multifocal ellipse, [2] polyellipse, [3] egglipse, [4] k-ellipse, [5] and Tschirnhaus'sche Eikurve (after Ehrenfried Walther von Tschirnhaus). They were first investigated by James Clerk Maxwell in 1846 ...
Mathematicians have several phrases to describe proofs or proof techniques. These are often used as hints for filling in tedious details. angle chasing Used to describe a geometrical proof that involves finding relationships between the various angles in a diagram. [3] back-of-the-envelope calculation