The conventional symbol for current is I, which originates from the French phrase intensité de courant, or in English current intensity. This phrase is frequently used when discussing the value of an ...
In statistics, the hat matrix, H, sometimes also called influence matrix and projection matrix, maps the vector of observed values to the vector of fitted values. It describes the influence each obser ...
In physics, and electronics, the henry (symbol H) is the SI derived unit of inductance. It is named after Joseph Henry (1797–1878), the American scientist who discovered electromagnetic induction ind ...
An alternative form of the unit step, as a function of a discrete variable n:H=\begin{cases} 0, n 0, \\ 1, n \ge 0, \end{cases} where n is an integer. Unlike the usual (not discrete) case, the defi ...
Bessel's equation arises when finding separable solutions to Laplace's equation and the Helmholtz equation in cylindrical or spherical coordinates. Bessel functions are therefore especially important ...
Main article: Operator (physics) § Operators in quantum mechanicsThe Hamiltonian is the sum of the kinetic energies of all the particles, plus the potential energy of the particles associated with th ...
The word enthalpy is based on the Greek enthalpein (?νθ?λπειν), which means "to warm in". It comes from the Classical Greek prefix ?ν- en-, meaning "to put into", and the verb θ?λπει ...
Momentum has a direction as well as magnitude. Quantities that have both a magnitude and a direction are known as vector quantities. Because momentum has a direction, it can be used to predict the res ...
A Green's function, G(x, s), of a linear differential operator L = L(x) acting on distributions over a subset of the Euclidean space Rn, at a point s, is any solution ofLG(x,s)=\delta(x-s),(1)where \d ...
According to the law of universal gravitation, the attractive force (F) between two bodies is directly proportional to the product of their masses (m1 and m2), and inversely proportional to the square ...
In a simple manner, with respect to STP reacting systems, a general rule of thumb is that every system seeks to achieve a minimum of free energy.Hence, out of this general natural tendency, a quantita ...
The Einstein tensor \mathbf{G} is a rank 2 tensor defined over pseudo-Riemannian manifolds. In index-free notation it is defined as\mathbf{G}=\mathbf{R}-\frac{1}{2}\mathbf{g}R,where \mathbf{R} is the ...
The Helmholtz energy is defined as:A \equiv U-TS\,whereA is the Helmholtz free energy (SI: joules, CGS: ergs),U is the internal energy of the system (SI: joules, CGS: ergs),T is the absolute temperatu ...
Population studies from the mid-20th century onwards show topical fluoride reduces dental caries. This was first attributed to the conversion of tooth enamel hydroxyapatite into the more durable fluor ...
Fluorine has a rich chemistry, encompassing organic and inorganic domains. It combines with metals, nonmetals, metalloids, and most noble gases, and usually assumes an oxidation state of ?1. Fluorine ...
