HOME  TheInfoList.com 
Ellipsoid An ellipsoid is a surface that may be obtained from a sphere by deforming it by means of directional scalings, or more generally, of an affine transformation. An ellipsoid is a quadric surface, that is a surface that may be defined as the zero set of a polynomial of degree two in three variables. Among quadric surfaces, an ellipsoid is characterized by either of the two following properties. Every planar cross section is either an ellipse, or is empty, or is reduced to a single point (this explains the name, meaning "ellipse like"). It is bounded, which means that it may be enclosed in a sufficiently large sphere. An ellipsoid has three pairwise perpendicular axes of symmetry which intersect at a center of symmetry, called the center of the ellipsoid. The line segments that are delimited on the axes of symmetry by the ellipsoid are called the principal axes, or simply axes of the ellipsoid [...More...]  "Ellipsoid" on: Wikipedia Yahoo 

MathWorld MathWorld is an online mathematics reference work, created and largely written by Eric W. Weisstein. It is sponsored by and licensed to Wolfram Research, Inc. Wolfram Research, Inc. and was partially funded by the National Science Foundation's National Science Digital Library grant to the University of Illinois at Urbana–Champaign.Contents1 History 2 CRC lawsuit 3 See also 4 References 5 External linksHistory[edit] Eric W. Weisstein, the creator of the site, was a physics and astronomy student who got into the habit of writing notes on his mathematical readings. In 1995 he put his notes online and called it "Eric's Treasure Trove of Mathematics." It contained hundreds of pages/articles, covering a wide range of mathematical topics. The site became popular as an extensive single resource on mathematics on the web. Weisstein continuously improved the notes and accepted corrections and comments from online readers [...More...]  "MathWorld" on: Wikipedia Yahoo 

Elliptic Cylinder A cylinder (from Greek κύλινδρος – kulindros, "roller, tumbler"[1]), has traditionally been a threedimensional solid, one of the most basic of curvilinear geometric shapes. It is the idealized version of a solid physical tin can having lids on top and bottom. This traditional view is still used in elementary treatments of geometry, but the advanced mathematical viewpoint has shifted to the infinite curvilinear surface and this is how a cylinder is now defined in various modern branches of geometry and topology. The shift in the basic meaning (solid versus surface) has created some ambiguity with terminology. It is generally hoped that context makes the meaning clear [...More...]  "Elliptic Cylinder" on: Wikipedia Yahoo 

Implicit Surface In mathematics an implicit surface is a surface in Euclidean space defined by an equation F ( x , y , z ) = 0. displaystyle F(x,y,z)=0. An implicit surface is the set of zeros of a function of three variables. Implicit means that the equation is not solved for x or y or z. The graph of a function is usually described by an equation z = f ( x , y ) displaystyle z=f(x,y) and is called an explicit representation [...More...]  "Implicit Surface" on: Wikipedia Yahoo 

Real Number In mathematics, a real number is a value that represents a quantity along a line. The adjective real in this context was introduced in the 17th century by René Descartes, who distinguished between real and imaginary roots of polynomials. The real numbers include all the rational numbers, such as the integer −5 and the fraction 4/3, and all the irrational numbers, such as √2 (1.41421356..., the square root of 2, an irrational algebraic number). Included within the irrationals are the transcendental numbers, such as π (3.14159265...). Real numbers can be thought of as points on an infinitely long line called the number line or real line, where the points corresponding to integers are equally spaced. Any real number can be determined by a possibly infinite decimal representation, such as that of 8.632, where each consecutive digit is measured in units one tenth the size of the previous one [...More...]  "Real Number" on: Wikipedia Yahoo 

Semimajor Axis In geometry, the major axis of an ellipse is its longest diameter: a line segment that runs through the center and both foci, with ends at the widest points of the perimeter. The semimajor axis is one half of the major axis, and thus runs from the centre, through a focus, and to the perimeter [...More...]  "Semimajor Axis" on: Wikipedia Yahoo 

Semiminor Axis In geometry, the major axis of an ellipse is its longest diameter: a line segment that runs through the center and both foci, with ends at the widest points of the perimeter. The semimajor axis is one half of the major axis, and thus runs from the centre, through a focus, and to the perimeter [...More...]  "Semiminor Axis" on: Wikipedia Yahoo 

Euclidean Vector In mathematics, physics, and engineering, a Euclidean vector (sometimes called a geometric[1] or spatial vector,[2] or—as here—simply a vector) is a geometric object that has magnitude (or length) and direction. Vectors can be added to other vectors according to vector algebra. A Euclidean vector Euclidean vector is frequently represented by a line segment with a definite direction, or graphically as an arrow, connecting an initial point A with a terminal point B,[3] and denoted by A B → . displaystyle overrightarrow AB [...More...]  "Euclidean Vector" on: Wikipedia Yahoo 

Circumscribed In geometry, the circumscribed circle or circumcircle of a polygon is a circle which passes through all the vertices of the polygon. The center of this circle is called the circumcenter and its radius is called the circumradius. A polygon which has a circumscribed circle is called a cyclic polygon (sometimes a concyclic polygon, because the vertices are concyclic). All regular simple polygons, all isosceles trapezoids, all triangles and all rectangles are cyclic. A related notion is the one of a minimum bounding circle, which is the smallest circle that completely contains the polygon within it [...More...]  "Circumscribed" on: Wikipedia Yahoo 

Positive Definite Matrix In linear algebra, a symmetric n displaystyle n × n displaystyle n real matrix M displaystyle M is said to be positive definite if the scalar z T M z displaystyle z^ mathrm T Mz is strictly positive for every nonzero column vector z displaystyle z of n displaystyle n real numbers. Here z T displaystyle z^ mathrm T denotes the transpose of z displaystyle z .[1] More generally, an n displaystyle n × n displaystyle n Hermitian matrix M displaystyle M is said to be positive definite if the scalar z ∗ M z displaystyle z^ * Mz is strictly positive for every nonzero column vector z displaystyle z of n displaystyle n complex numbers [...More...]  "Positive Definite Matrix" on: Wikipedia Yahoo 

Eigenvalue In linear algebra, an eigenvector or characteristic vector of a linear transformation is a nonzero vector that only changes by a scalar factor when that linear transformation is applied to it. More formally, if T is a linear transformation from a vector space V over a field F into itself and v is a vector in V that is not the zero vector, then v is an eigenvector of T if T(v) is a scalar multiple of v [...More...]  "Eigenvalue" on: Wikipedia Yahoo 

Inscribed In geometry, an inscribed planar shape or solid is one that is enclosed by and "fits snugly" inside another geometric shape or solid. To say that "figure F is inscribed in figure G" means precisely the same thing as "figure G is circumscribed about figure F". A circle or ellipse inscribed in a convex polygon (or a sphere or ellipsoid inscribed in a convex polyhedron) is tangent to every side or face of the outer figure (but see Inscribed sphere for semantic variants). A polygon inscribed in a circle, ellipse, or polygon (or a polyhedron inscribed in a sphere, ellipsoid, or polyhedron) has each vertex on the outer figure; if the outer figure is a polygon or polyhedron, there must be a vertex of the inscribed polygon or polyhedron on each side of the outer figure [...More...]  "Inscribed" on: Wikipedia Yahoo 

Rectangular Cuboid In geometry, a cuboid is a convex polyhedron bounded by six quadrilateral faces, whose polyhedral graph is the same as that of a cube. While mathematical literature refers to any such polyhedron as a cuboid,[1] other sources use "cuboid" to refer to a shape of this type in which each of the faces is a rectangle (and so each pair of adjacent faces meets in a right angle); this more restrictive type of cuboid is also known as a rectangular cuboid, right cuboid, rectangular box, rectangular hexahedron, right rectangular prism, or rectangular parallelepiped.[2]Contents1 General cuboids 2 Rectangular cuboid2.1 Nets3 See also 4 References 5 External linksGeneral cuboids[edit] By Euler's formula the numbers of faces F, of vertices V, and of edges E of any convex polyhedron are related by the formula F + V = E + 2 [...More...]  "Rectangular Cuboid" on: Wikipedia Yahoo 

Surface Area The surface area of a solid object is a measure of the total area that the surface of the object occupies. The mathematical definition of surface area in the presence of curved surfaces is considerably more involved than the definition of arc length of onedimensional curves, or of the surface area for polyhedra (i.e., objects with flat polygonal faces), for which the surface area is the sum of the areas of its faces. Smooth surfaces, such as a sphere, are assigned surface area using their representation as parametric surfaces. This definition of surface area is based on methods of infinitesimal calculus and involves partial derivatives and double integration. A general definition of surface area was sought by Henri Lebesgue Henri Lebesgue and Hermann Minkowski Hermann Minkowski at the turn of the twentieth century [...More...]  "Surface Area" on: Wikipedia Yahoo 

Elliptic Integral In integral calculus, elliptic integrals originally arose in connection with the problem of giving the arc length of an ellipse. They were first studied by Giulio Fagnano and Leonhard Euler (c. 1750). Modern mathematics defines an "elliptic integral" as any function f which can be expressed in the form f ( x ) = ∫ c x R ( t , P ( t ) ) d t , displaystyle f(x)=int _ c ^ x Rleft(t, sqrt P(t) right),dt, where R is a rational function of its two arguments, P is a polynomial of degree 3 or 4 with no repeated roots, and c is a constant. In general, integrals in this form cannot be expressed in terms of elementary functions. Exceptions to this general rule are when P has repeated roots, or when R(x,y) contains no odd powers of y [...More...]  "Elliptic Integral" on: Wikipedia Yahoo 

Elementary Function In mathematics, an elementary function is a function of one variable which is the composition of a finite number of arithmetic operations (+ – × ÷), exponentials, logarithms, constants, and solutions of algebraic equations (a generalization of nth roots). The elementary functions include:Powers of x : x , x 2 , x 3 displaystyle x:x,x^ 2 ,x^ 3 ,etc Roots of x : x , x 3 , displaystyle x: sqrt x , sqrt[ 3 ] x , , etc Exponentials: e x displaystyle e^ x Logarithms: log x Trig Functions Inverse Trig Functions Hyperbolic Trig Functions All functions obtained by substituting x for any of the previous functions All functions obtained by adding, subtracting, multiplyi [...More...]  "Elementary Function" on: Wikipedia Yahoo 