Editing Equation (section)

== Types of equations ==
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Equations can be classified according to the types of [[Operation (mathematics)|operations]] and quantities involved. Important types include:
* An [[algebraic equation]] or [[polynomial]] equation is an equation in which both sides are polynomials (see also [[system of polynomial equations]]). These are further classified by [[degree of a polynomial|degree]]:
** [[linear equation]] for degree one
** [[quadratic equation]] for degree two
** [[cubic equation]] for degree three
** [[quartic equation]] for degree four
** [[quintic equation]] for degree five
** [[sextic equation]] for degree six
** [[septic equation]] for degree seven
** [[octic equation]] for degree eight
* A [[Diophantine equation]] is an equation where the unknowns are required to be [[integer]]s
* A [[transcendental equation]] is an equation involving a [[transcendental function]] of its unknowns
* A [[parametric equation]] is an equation in which the solutions for the variables are expressed as functions of some other variables, called [[parameter]]s appearing in the equations
* A [[functional equation]] is an equation in which the unknowns are [[Function (mathematics)|functions]] rather than simple quantities
* Equations involving derivatives, integrals and finite differences:
** A [[differential equation]] is a functional equation involving [[derivative]]s of the unknown functions, where the function and its derivatives are evaluated at the same point, such as <math>f'(x) = x^2</math>.  Differential equations are subdivided into [[ordinary differential equation]]s for functions of a single variable and [[partial differential equation]]s for functions of multiple variables
** An [[integral equation]] is a functional equation involving the [[antiderivative]]s of the unknown functions.  For functions of one variable, such an equation differs from a differential equation primarily through a change of variable substituting the function by its derivative, however this is not the case when the integral is taken over an open surface
** An [[integro-differential equation]] is a functional equation involving both the [[derivative]]s and the [[antiderivative]]s of the unknown functions.  For functions of one variable, such an equation differs from integral and differential equations through a similar change of variable. 
** A [[functional differential equation]] of [[delay differential equation]] is a function equation involving [[derivative]]s of the unknown functions, evaluated at multiple points, such as <math>f'(x) = f(x-2)</math>
** A [[difference equation]] is an equation where the unknown is a function ''f'' that occurs in the equation through ''f''(''x''), ''f''(''x''−1), ..., ''f''(''x''−''k''), for some whole integer ''k'' called the ''order'' of the equation. If ''x'' is restricted to be an integer, a difference equation is the same as a [[recurrence relation]]
** A [[stochastic differential equation]] is a differential equation in which one or more of the terms is a [[stochastic process]]