In mathematics , an equation is a mathematical formula that expresses the equality of two expressions , by connecting them with the equals sign = . The word equation and its cognates in other languages may have subtly different meanings; for example, in French an équation is defined as containing one or more variables , while in English , any well-formed formula consisting of two expressions related with an equals sign is an equation.
48-470: [REDACTED] Look up unknown or Unknowns in Wiktionary, the free dictionary. Unknown or The Unknown may refer to: Film and television [ edit ] Film [ edit ] The Unknown (1915 comedy film) , Australian silent film The Unknown (1915 drama film) , American silent drama film The Unknown (1927 film) ,
96-410: A , b , c {\displaystyle a,b,c} and d {\displaystyle d} are real numbers and x , y , z {\displaystyle x,y,z} are the unknowns that correspond to the coordinates of a point in the system given by the orthogonal grid. The values a , b , c {\displaystyle a,b,c} are the coordinates of
144-651: A 1998 book in the Animorphs series by K. A. Applegate The Unknown (hypertext novel) , a 1999 web-based hypertext novel written by William Gillespie, Scott Rettberg and Dirk Stratton with Frank Marquardt The Unknown (1963 anthology) , an anthology of fantasy fiction short stories edited by D. R. Bensen and illustrated by Edd Cartier The Unknown , a comic book mini-series by Mark Waid Music [ edit ] The Unknown (Madeline Juno album) (2014) Unknown (Rasputina album) (2015) The Unknown (The Vision Bleak album) (2016) The Unknown ,
192-595: A 1998 book in the Animorphs series by K. A. Applegate The Unknown (hypertext novel) , a 1999 web-based hypertext novel written by William Gillespie, Scott Rettberg and Dirk Stratton with Frank Marquardt The Unknown (1963 anthology) , an anthology of fantasy fiction short stories edited by D. R. Bensen and illustrated by Edd Cartier The Unknown , a comic book mini-series by Mark Waid Music [ edit ] The Unknown (Madeline Juno album) (2014) Unknown (Rasputina album) (2015) The Unknown (The Vision Bleak album) (2016) The Unknown ,
240-503: A mathematical model or computer simulation of a relatively complex system. In Euclidean geometry , it is possible to associate a set of coordinates to each point in space, for example by an orthogonal grid. This method allows one to characterize geometric figures by equations. A plane in three-dimensional space can be expressed as the solution set of an equation of the form a x + b y + c z + d = 0 {\displaystyle ax+by+cz+d=0} , where
288-567: A 2014 album by Dillon "The Unknown" (song) , by 10 Years, 2019 "The Unknown", a song by Crossfade from Crossfade , 2004 "The Unknown (Strength)", a song by In Hearts Wake from Divination , 2012 "The Unknown", a song by Imagine Dragons from the deluxe edition of Smoke + Mirrors , 2015 "The Unknown", a song by Shadows Fall from Fire from the Sky , 2012 "Unknown", a song by Reks from The Greatest X , 2016 Science and mathematics [ edit ] Unknown (mathematics) ,
336-518: A 2014 album by Dillon "The Unknown" (song) , by 10 Years, 2019 "The Unknown", a song by Crossfade from Crossfade , 2004 "The Unknown (Strength)", a song by In Hearts Wake from Divination , 2012 "The Unknown", a song by Imagine Dragons from the deluxe edition of Smoke + Mirrors , 2015 "The Unknown", a song by Shadows Fall from Fire from the Sky , 2012 "Unknown", a song by Reks from The Greatest X , 2016 Science and mathematics [ edit ] Unknown (mathematics) ,
384-735: A conic. The use of equations allows one to call on a large area of mathematics to solve geometric questions. The Cartesian coordinate system transforms a geometric problem into an analysis problem, once the figures are transformed into equations; thus the name analytic geometry . This point of view, outlined by Descartes , enriches and modifies the type of geometry conceived of by the ancient Greek mathematicians. Currently, analytic geometry designates an active branch of mathematics. Although it still uses equations to characterize figures, it also uses other sophisticated techniques such as functional analysis and linear algebra . In Cartesian geometry , equations are used to describe geometric figures . As
432-407: A linear system is an assignment of numbers to the variables such that all the equations are simultaneously satisfied. A solution to the system above is given by since it makes all three equations valid. The word " system " indicates that the equations are to be considered collectively, rather than individually. In mathematics, the theory of linear systems is a fundamental part of linear algebra ,
480-833: A location in Over the Garden Wall The Unknown, a character in Willy's Chocolate Experience The Unknown , a sculpture by Kenny Hunter Unknown, a Unicode script The Unknowns , a self-proclaimed ethical hacking group People [ edit ] Unknown Hinson (born 1954), musician and performer The Unknown Comic (born 1945), Canadian actor and comedian The Unknown DJ , American disc jockey and record producer Unknown T (born 1998), British rapper See also [ edit ] The Great Unknown (disambiguation) L'Inconnue de la Seine (died c. 1880), unidentified young woman whose death mask
528-657: A location in Over the Garden Wall The Unknown, a character in Willy's Chocolate Experience The Unknown , a sculpture by Kenny Hunter Unknown, a Unicode script The Unknowns , a self-proclaimed ethical hacking group People [ edit ] Unknown Hinson (born 1954), musician and performer The Unknown Comic (born 1945), Canadian actor and comedian The Unknown DJ , American disc jockey and record producer Unknown T (born 1998), British rapper See also [ edit ] The Great Unknown (disambiguation) L'Inconnue de la Seine (died c. 1880), unidentified young woman whose death mask
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#1732765276989576-406: A silent horror film starring Lon Chaney The Unknown (1936 film) , a German drama film The Unknown (1946 film) , a mystery film The Unknown (1964 film) , a Polish war film Anjaane: The Unknown , a 2005 Bollywood horror movie The Unknown , a 2005 action/thriller starring Miles O'Keeffe Unknown (2006 film) , a thriller starring James Caviezel Unknown (2011 film) ,
624-406: A silent horror film starring Lon Chaney The Unknown (1936 film) , a German drama film The Unknown (1946 film) , a mystery film The Unknown (1964 film) , a Polish war film Anjaane: The Unknown , a 2005 Bollywood horror movie The Unknown , a 2005 action/thriller starring Miles O'Keeffe Unknown (2006 film) , a thriller starring James Caviezel Unknown (2011 film) ,
672-500: A solution that is an algebraic expression , with a finite number of operations involving just those coefficients (i.e., can be solved algebraically ). This can be done for all such equations of degree one, two, three, or four; but equations of degree five or more cannot always be solved in this way, as the Abel–Ruffini theorem demonstrates. A large amount of research has been devoted to compute efficiently accurate approximations of
720-408: A subject which is used in many parts of modern mathematics. Computational algorithms for finding the solutions are an important part of numerical linear algebra , and play a prominent role in physics , engineering , chemistry , computer science , and economics . A system of non-linear equations can often be approximated by a linear system (see linearization ), a helpful technique when making
768-429: A system of equations into an equivalent one – provided that the operations are meaningful for the expressions they are applied to: If some function is applied to both sides of an equation, the resulting equation has the solutions of the initial equation among its solutions, but may have further solutions called extraneous solutions . For example, the equation x = 1 {\displaystyle x=1} has
816-547: A thriller starring Liam Neeson Unknowns ( Desconocidas ), a 2022 film by Venezuelan director Luis Fernández TV [ edit ] Het Onbekende (Dutch for: The Unknown ), Dutch television show Unknown , a 2024 web series starring Chris Chiu "The Unknown" ( Star Wars: The Clone Wars ) , a 2014 episode of the TV series Literature [ edit ] Unknown (magazine) , an American pulp fantasy fiction magazine published from 1939 to 1943 The Unknown ,
864-499: A thriller starring Liam Neeson Unknowns ( Desconocidas ), a 2022 film by Venezuelan director Luis Fernández TV [ edit ] Het Onbekende (Dutch for: The Unknown ), Dutch television show Unknown , a 2024 web series starring Chris Chiu "The Unknown" ( Star Wars: The Clone Wars ) , a 2014 episode of the TV series Literature [ edit ] Unknown (magazine) , an American pulp fantasy fiction magazine published from 1939 to 1943 The Unknown ,
912-614: A variable that appears in an equation for which a solution is sought Unknown, the ongoing answer to an open problem Video games [ edit ] Unknown (video game) or Amnesia: The Dark Descent , a 2010 video game Unknown ( Tekken ) , a character in Tekken Other uses [ edit ] "The Unknown" ( Over the Garden Wall ) , an episode of Over the Garden Wall The Unknown,
960-418: A variable that appears in an equation for which a solution is sought Unknown, the ongoing answer to an open problem Video games [ edit ] Unknown (video game) or Amnesia: The Dark Descent , a 2010 video game Unknown ( Tekken ) , a character in Tekken Other uses [ edit ] "The Unknown" ( Over the Garden Wall ) , an episode of Over the Garden Wall The Unknown,
1008-429: A vector perpendicular to the plane defined by the equation. A line is expressed as the intersection of two planes, that is as the solution set of a single linear equation with values in R 2 {\displaystyle \mathbb {R} ^{2}} or as the solution set of two linear equations with values in R 3 . {\displaystyle \mathbb {R} ^{3}.} A conic section
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#17327652769891056-426: Is univariate if it involves only one variable . On the other hand, a polynomial equation may involve several variables, in which case it is called multivariate (multiple variables, x, y, z, etc.). For example, is a univariate algebraic (polynomial) equation with integer coefficients and is a multivariate polynomial equation over the rational numbers. Some polynomial equations with rational coefficients have
1104-478: Is a polynomial equation (commonly called also an algebraic equation ) in which the two sides are polynomials . The sides of a polynomial equation contain one or more terms . For example, the equation has left-hand side A x 2 + B x + C − y {\displaystyle Ax^{2}+Bx+C-y} , which has four terms, and right-hand side 0 {\displaystyle 0} , consisting of just one term. The names of
1152-414: Is analogous to a weighing scale , balance, or seesaw . Each side of the equation corresponds to one side of the balance. Different quantities can be placed on each side: if the weights on the two sides are equal, the scale balances, and in analogy, the equality that represents the balance is also balanced (if not, then the lack of balance corresponds to an inequality represented by an inequation ). In
1200-529: Is different from Wikidata All article disambiguation pages All disambiguation pages unknown [REDACTED] Look up unknown or Unknowns in Wiktionary, the free dictionary. Unknown or The Unknown may refer to: Film and television [ edit ] Film [ edit ] The Unknown (1915 comedy film) , Australian silent film The Unknown (1915 drama film) , American silent drama film The Unknown (1927 film) ,
1248-416: Is different from Wikidata All article disambiguation pages All disambiguation pages Unknown (mathematics) Solving an equation containing variables consists of determining which values of the variables make the equality true. The variables for which the equation has to be solved are also called unknowns , and the values of the unknowns that satisfy the equality are called solutions of
1296-467: Is limited to between 0 and 45 degrees, one may use the above identity for the product to give: yielding the following solution for θ: Since the sine function is a periodic function , there are infinitely many solutions if there are no restrictions on θ . In this example, restricting θ to be between 0 and 45 degrees would restrict the solution to only one number. Algebra studies two main families of equations: polynomial equations and, among them,
1344-400: Is the difference of two squares : which is true for all x and y . Trigonometry is an area where many identities exist; these are useful in manipulating or solving trigonometric equations . Two of many that involve the sine and cosine functions are: and which are both true for all values of θ . For example, to solve for the value of θ that satisfies the equation: where θ
1392-406: Is the intersection of a cone with equation x 2 + y 2 = z 2 {\displaystyle x^{2}+y^{2}=z^{2}} and a plane. In other words, in space, all conics are defined as the solution set of an equation of a plane and of the equation of a cone just given. This formalism allows one to determine the positions and the properties of the focuses of
1440-412: Is written as two expressions , connected by an equals sign ("="). The expressions on the two sides of the equals sign are called the "left-hand side" and "right-hand side" of the equation. Very often the right-hand side of an equation is assumed to be zero. This does not reduce the generality, as this can be realized by subtracting the right-hand side from both sides. The most common type of equation
1488-447: The real or complex solutions of a univariate algebraic equation (see Root finding of polynomials ) and of the common solutions of several multivariate polynomial equations (see System of polynomial equations ). A system of linear equations (or linear system ) is a collection of linear equations involving one or more variables . For example, is a system of three equations in the three variables x , y , z . A solution to
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1536-417: The variables suggest that x and y are unknowns, and that A , B , and C are parameters , but this is normally fixed by the context (in some contexts, y may be a parameter, or A , B , and C may be ordinary variables). An equation is analogous to a scale into which weights are placed. When equal weights of something (e.g., grain) are placed into the two pans, the two weights cause
1584-484: The Cartesian coordinate system, geometric shapes (such as curves ) can be described by Cartesian equations: algebraic equations involving the coordinates of the points lying on the shape. For example, a circle of radius 2 in a plane, centered on a particular point called the origin, may be described as the set of all points whose coordinates x and y satisfy the equation x + y = 4 . A parametric equation for
1632-526: The coefficients and solutions are integers . The techniques used are different and come from number theory . These equations are difficult in general; one often searches just to find the existence or absence of a solution, and, if they exist, to count the number of solutions. In general, an algebraic equation or polynomial equation is an equation of the form where P and Q are polynomials with coefficients in some field (e.g., rational numbers , real numbers , complex numbers ). An algebraic equation
1680-416: The equation with R unspecified is the general equation for the circle. Usually, the unknowns are denoted by letters at the end of the alphabet, x , y , z , w , ..., while coefficients (parameters) are denoted by letters at the beginning, a , b , c , d , ... . For example, the general quadratic equation is usually written ax + bx + c = 0. The process of finding
1728-427: The equation. There are two kinds of equations: identities and conditional equations. An identity is true for all values of the variables. A conditional equation is only true for particular values of the variables. The " = " symbol, which appears in every equation, was invented in 1557 by Robert Recorde , who considered that nothing could be more equal than parallel straight lines with the same length. An equation
1776-420: The equations that are considered, such as implicit equations or parametric equations , have infinitely many solutions, the objective is now different: instead of giving the solutions explicitly or counting them, which is impossible, one uses equations for studying properties of figures. This is the starting idea of algebraic geometry , an important area of mathematics. One can use the same principle to specify
1824-511: The extraneous solution, x = − 1. {\displaystyle x=-1.} Moreover, if the function is not defined at some values (such as 1/ x , which is not defined for x = 0), solutions existing at those values may be lost. Thus, caution must be exercised when applying such a transformation to an equation. The above transformations are the basis of most elementary methods for equation solving , as well as some less elementary ones, like Gaussian elimination . An equation
1872-403: The illustration, x , y and z are all different quantities (in this case real numbers ) represented as circular weights, and each of x , y , and z has a different weight. Addition corresponds to adding weight, while subtraction corresponds to removing weight from what is already there. When equality holds, the total weight on each side is the same. Equations often contain terms other than
1920-459: The position of any point in three- dimensional space by the use of three Cartesian coordinates, which are the signed distances to three mutually perpendicular planes (or, equivalently, by its perpendicular projection onto three mutually perpendicular lines). The invention of Cartesian coordinates in the 17th century by René Descartes revolutionized mathematics by providing the first systematic link between Euclidean geometry and algebra . Using
1968-454: The scale to be in balance and are said to be equal. If a quantity of grain is removed from one pan of the balance, an equal amount of grain must be removed from the other pan to keep the scale in balance. More generally, an equation remains in balance if the same operation is performed on each side. Two equations or two systems of equations are equivalent , if they have the same set of solutions. The following operations transform an equation or
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2016-432: The solution x = 1. {\displaystyle x=1.} Raising both sides to the exponent of 2 (which means applying the function f ( s ) = s 2 {\displaystyle f(s)=s^{2}} to both sides of the equation) changes the equation to x 2 = 1 {\displaystyle x^{2}=1} , which not only has the previous solution but also introduces
2064-416: The solutions, or, in case of parameters, expressing the unknowns in terms of the parameters, is called solving the equation . Such expressions of the solutions in terms of the parameters are also called solutions . A system of equations is a set of simultaneous equations , usually in several unknowns for which the common solutions are sought. Thus, a solution to the system is a set of values for each of
2112-467: The special case of linear equations . When there is only one variable, polynomial equations have the form P ( x ) = 0, where P is a polynomial , and linear equations have the form ax + b = 0, where a and b are parameters . To solve equations from either family, one uses algorithmic or geometric techniques that originate from linear algebra or mathematical analysis . Algebra also studies Diophantine equations where
2160-476: The unknowns, which together form a solution to each equation in the system. For example, the system has the unique solution x = −1, y = 1. An identity is an equation that is true for all possible values of the variable(s) it contains. Many identities are known in algebra and calculus. In the process of solving an equation, an identity is often used to simplify an equation, making it more easily solvable. In algebra, an example of an identity
2208-460: The unknowns. These other terms, which are assumed to be known , are usually called constants , coefficients or parameters . An example of an equation involving x and y as unknowns and the parameter R is When R is chosen to have the value of 2 ( R = 2), this equation would be recognized in Cartesian coordinates as the equation for the circle of radius of 2 around the origin. Hence,
2256-672: Was the model for the CPR doll Resusci Anne Unknown known Unknown Soldier (disambiguation) Unown , a Pokémon species Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title Unknown . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Unknown&oldid=1255297194 " Categories : Disambiguation pages Disambiguation pages with given-name-holder lists Hidden categories: Short description
2304-623: Was the model for the CPR doll Resusci Anne Unknown known Unknown Soldier (disambiguation) Unown , a Pokémon species Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title Unknown . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Unknown&oldid=1255297194 " Categories : Disambiguation pages Disambiguation pages with given-name-holder lists Hidden categories: Short description
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