An **equation**, in a mathematical context, is generally understood to mean a mathematical statement that asserts the equality of two expressions. In modern notation, this is written by placing the expressions on either side of an equals sign (=), for example

asserts that *x*+3 is equal to 5. The = symbol was invented by Robert Recorde (1510–1558), who considered that nothing could be more equal than parallel straight lines with the same length.

Centuries ago, the word "equation" frequently meant what we now usually call "correction" or "adjustment". This meaning is still occasionally found, especially in names which were originally given long ago. The "equation of time", for example, is a correction that must be applied to the reading of a sundial in order to obtain mean time, as would be shown by a clock.

Read more about Equation: Knowns and Unknowns, Analogous Illustration, Types of Equations, Identities, Properties

### Other articles related to "equation, equations":

... can be used to derive the Brownian motion of a particle from the Langevin

**equation**... According to that

**equation**, the motion of a particle of mass m with velocity v is governed by Newton's second law where Frnd is a random force representing the random collisions of the particle and ... The dot product of this

**equation**with the position vector r, after averaging, yields the

**equation**for Brownian motion (since the random force Frnd is uncorrelated with ...

... where there is no superconducting current and the

**equation**for ψ simplifies to This

**equation**has a trivial solution ψ = 0 ... Below the superconducting transition temperature, the above

**equation**is expected to have a non-trivial solution (that is ψ ≠ 0) ... Under this assumption the

**equation**above can be rearranged into When the right hand side of this

**equation**is positive, there is a nonzero solution for ψ (remem ...

... For a stationary shock, and for the 1D Euler

**equations**we have In view of

**equation**(12) we can simplify

**equation**(14) to which is a statement of Bernoulli's principle ... Substituting and from

**equations**(12) and (13) into

**equation**(15) yields the following relationship where represents specific enthalpy of the fluid ... Eliminating internal energy in

**equation**(15) by use of the

**equation**-of-state,

**equation**( 4), yields From physical considerations it is clear that both the upstream and downstream ...

**Equation**- Properties

... If an

**equation**in algebra is known to be true, the following operations may be used to produce another true

**equation**Any real number can be added to both sides ... For example, the

**equation**has 2 sets of solutions (with any x) and (with any y) ... applying the function to both sides of the

**equation**) changes our

**equation**into, which not only has all the previous solutions but also introduces a new set of extraneous solutions, with and x ...

**Equation**

... In mathematics, Poisson's

**equation**is a partial differential

**equation**of elliptic type with broad utility in electrostatics, mechanical engineering and theoretical physics ...

### Famous quotes containing the word equation:

“Jail sentences have many functions, but one is surely to send a message about what our society abhors and what it values. This week, the *equation* was twofold: female infidelity twice as bad as male abuse, the life of a woman half as valuable as that of a man. The killing of the woman taken in adultery has a long history and survives today in many cultures. One of those is our own.”

—Anna Quindlen (b. 1952)

“A nation fights well in proportion to the amount of men and materials it has. And the other *equation* is that the individual soldier in that army is a more effective soldier the poorer his standard of living has been in the past.”

—Norman Mailer (b. 1923)