# Definitions for **quadric**ˈkwɒd rɪk

### This page provides all possible meanings and translations of the word **quadric**

### Random House Webster's College Dictionary

quad•ricˈkwɒd rɪk(adj.)

**Category:**Math**Ref:**quadratic.(n.)a surface such as an ellipsoid or paraboloid as defined by a second-degree equation in three real variables.

**Category:**Math

#### Origin of **quadric**:

1855–60

### Princeton's WordNet

quadric, quadric surface(noun)

a curve or surface whose equation (in Cartesian coordinates) is of the second degree

### Wiktionary

quadric(Noun)

A surface whose shape is defined in terms of a quadratic equation

### Webster Dictionary

Quadric(adj)

of or pertaining to the second degree

Quadric(noun)

a quantic of the second degree. See Quantic

Quadric(noun)

a surface whose equation in three variables is of the second degree. Spheres, spheroids, ellipsoids, paraboloids, hyperboloids, also cones and cylinders with circular bases, are quadrics

### Freebase

Quadric

In mathematics, a quadric, or quadric surface, is any D-dimensional hypersurface in-dimensional space defined as the locus of zeros of a quadratic polynomial. In coordinates {x1, x2, ..., xD+1}, the general quadric is defined by the algebraic equation which may be compactly written in vector and matrix notation as: where x = {x1, x2, ..., xD+1} is a row vector, xT is the transpose of x, Q is a × matrix and P is a-dimensional row vector and R a scalar constant. The values Q, P and R are often taken to be real numbers or complex numbers, but in fact, a quadric may be defined over any ring. In general, the locus of zeros of a set of polynomials is known as an algebraic variety, and is studied in the branch of algebraic geometry. A quadric is thus an example of an algebraic variety. For the projective theory see quadric.

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"quadric." *Definitions.net.* STANDS4 LLC, 2014. Web. 21 Nov. 2014. <http://www.definitions.net/definition/quadric>.