## Frenet–Serret formulas

In **vector** calculus , the Frenet–Serret formulas describe the kinematic properties of a particle which moves along a continuous, differentiable curve in three-dimensional Euclidean space R 3 . More specifically, the formulas describe the derivatives of the so-called tangent, **normal**

**wikipedia.org**| 2011/4/13 20:20:16

## Surface normal

A surface **normal** , or simply **normal** , to a flat surface is a **vector** that is perpendicular to that surface. A **normal** to a non-flat surface at a point P on the surface is a **vector** perpendicular to the tangent plane to that surface at P . The word **normal** " is also used as an adjective

**wikipedia.org**| 2011/5/6 9:43:25

## Normal force

In mechanics , the **normal** force (occasionally N ) is the component, perpendicular to the surface of contact, of the contact force exerted on an object by, for example, the surface of a floor or wall, preventing the object from penetrating the surface. The **normal** force is one of the components

**wikipedia.org**| 2011/10/4 12:39:09

## Mean value analysis

after visiting queue i the customer will visit queue j . From this matrix we can calculate the **vector** known as the visit-ratio **vector** by solving the eigenvector-like equation V P = V . Let N j ( n ) be the mean number of customers in queue j when there are a total of n customers in

**wikipedia.org**| 2010/9/26 0:50:27

## Hesse normal form

The Hesse **normal** form named after Otto Hesse , is an equation used in analytic geometry , and describes a line in or a plane in Euclidean space . It is primarily used for calculating distances, and is written in **vector** notation as This equation is satisfied by all points P described

**wikipedia.org**| 2010/9/24 23:24:16

## Stress (mechanics)

force per square inch , which is abbreviated as psi. Contents 1 Introduction 1.1 **Normal** and shear stresses 1.2 Stress modeling (Cauchy) 1.3 Stress analysis 2 Theoretical background 3 Euler–Cauchy stress principle 3.1 Cauchy’s postulate 3.2 Cauchy’s fundamental

**wikipedia.org**| 2011/5/18 18:35:03

## Multivariate normal distribution

In probability theory and statistics , the multivariate **normal** distribution or multivariate Gaussian distribution , is a generalization of the one-dimensional ( univariate ) **normal** distribution to higher dimensions. A random **vector** is said to be multivariate normally distributed if every

**wikipedia.org**| 2011/9/26 18:38:32

## Jordan normal form

In linear algebra , Jordan **normal** form (often called Jordan canonical form ) [ 1 ] of a linear operator on a finite dimensional **vector** space is an upper triangular matrix of a particular form called Jordan matrix , representing the operator on some basis . The form is characterized

**wikipedia.org**| 2011/5/21 11:31:58

## Darboux frame

Contents 1 Darboux frame of an embedded curve 1.1 Definition 1.2 Geodesic curvature, **normal** curvature, and relative torsion 2 Darboux frame on a surface 2.1 The trihedron 2.2 Change of frame 2.3 Structure equations 2.4 Principal curves 3 Moving frames 3.1 Frames

**wikipedia.org**| 2010/9/26 15:36:27