Dictionary of Mathematics

The word Mathematics comes from the Greek word Mathema, which means ‘learning’, ‘study’, ‘Science’, and additionally came to have the narrower and more technical meaning , “Mathematical Study”. Mathematics plays a vital role in developing the power of logical reasoning and concentration.

Dictionary of Mathematicsglossary of math vocabulary, terms and definitions (www.mathsdictionary.in ) is an interactive website which is an array of innumerable concepts and definitions in a precise, simple and comprehensive way. They have been gradually and systematically developed.

This website delves into the various mathematical arenas and can be used as a handy reference guide by all. The exposition is simple and rigorous. It helps to increase understanding of concepts, thinking and reasoning power.

Rajinder

Friday, 1 November 2013

Z

Z

Z- axis : Axis passing through the origin and perpendicular to both X and Y – axes in three –dimensional coordinate system.
Z- coordinate : The distance of appoint from xy plane in 3-dimensional coordinate system.
z-intercept
The distance from the origin to the point where a curve intersects z-axis in three –dimensional coordinate system . In other words the point  at which a line crosses the z-axis.
Zenith : The highest point on the celestial sphere ( or in the sky ) directly overhead the observer.
Zero : The symbol is 0, also called cipher or naught. Its basic meaning is ‘nothing’

zero divisors
Non zero elements of a ring whose product is 0.
Zero Ring : The ring with only one element, its additive identity .
Zeta, Symbol, Z (Capital ) , ζ (lower case ) :  the sixth letter of Greek alphabet.
Zodiac : It denotes annual cycle of twelve stations along the elliptic path, followed by sun, that divide the ellipse into twelve equal zones of celestial longitude.
zero element
The element 0 is a zero element of a group if a+0=a and 0+a=a for all elements a.
Zone of Sphere
The portion of a sphere cut off  by two parallel planes is segment and the curved surface of spherical segment is zone of sphere.
Zorn’s Lema : Zorn’s Lema states that , if P is a partially ordered set such that every totally ordered subset of P has an upper bound in P, then P has a ( not necessarily unique ) maximal element.

 ZX – plane : The plane  formed by Z and Z axes. The equation of ZX plane is     Y = 0.




Y


X

X
X
Roman numeral for 10.
X , Y, Z –axes Syn. Coordinate axis
These are three mutually perpendicular axes in 3- dimensional Cartesian coordinate system. The X-axis is horizontal ; the Y- axis is vertical and Z- axis perpendicular to both X and Y – axis . This is most commonly used coordinate system representing position in space.

X , Y, Z – Coordinate Syn. Cartesian Coordinates ; The position  of a point in space is represented by x, y, z coordinates, usually written as ( x, y, z), where the coordinate is the perpendicular distance from the plane formed by the other two axes.
X , Y, Z  intercepts : These are the distance from the origin to the points at which a curve intersects at X , Y , and Z axes.
Xy , yz , zx planes Syn. Coordinate plans : The planes formed by two coordinate axes in three dimensional Euclidean space. The plane xy contains x and y axes ; yz plane contains y and z axes and zx plane contains z and x axes. The equations of these planes are z = 0, x = 0 and y = 0 respectively.
x-pentomino

A pentomino in the shape of the letter X.

W

Under Construction

V

v
V : Roman Symbol for 5
Value , Absolute : The absolute value of real no is its numerical value without regard to sign. The absolute value of a number can be considered as the distance between zero and that number.
Value of Expression : An expression consists of a set of operators, functions or keywords and its value is the outcome obtained after performing operations.
Value of Function : Value of function is the outcome obtained after assigning suitable value to the independent variable.
Vanish : A function vanishes when its value becomes zero.
Variable : A quantity usually represented by x that can take different values. An integer variable can have only integral values whereas  a real variable can have only fractional value also. In y = f(x) , x is independent variable and y is dependent variable.
Variance : In Statistics, variance is a measure of variability; the mean square deviation from the mean, that is , the mean of the squares of the differences between individual values of x and the mean value . The variance in a population is given by 2 = ( x- mean)2 / N
Variate : A random variable with a numerical value that is defined on a given sample space.
Variation : Deviation of a variable from the mean value.
Variation of Function : In an interval [a,b] , the variation of function takes place as the value of independent variable changes. For a function of constant value, there will not be any change in the value of the function.
Variable : A symbol whose value can change.
Vector : Any quantity which has both magnitude and direction at each point in space , as opposed to a scalar which has only magnitude. We represent a vector geometrically by an arrow of length proportional to its magnitude , pointing in the assigned direction. Any vectors can be represented in terms of its components along the coordinate axes XS, Y, and Z. a vector drawn from the origin to a given point is called position vector and is usually symbolized by r in rectangular Cartesian coordinates as r = xi + yj + zk.
Vector, Parallelogram of : A Parallelogram that is constructed in order to add two vectors, by drawing them to scale so that they form two adjacent sides of the parallelogram.
Vector analysis : A branch of Mathematics dealing with vectors, their relations and applications.
Vector Difference : see vectors in www.mathsdictionary.in
Vector multiplication : see vectors in www.mathsdictionary.in
Vector product. Syn.Cross Product : see vectors in www.mathsdictionary.in
Vector Projection : see vectors in www.mathsdictionary.in
Vector Space : see vectors in www.mathsdictionary.in
Vector Sum : see vectors in www.mathsdictionary.in
Velocity : The rate of change of position. Velocity is a vector quantity.
            Velocity = displacement / time

Velocity of Light : Usually  denoted by c . its value is 3 x 1010 m/s.
Venn Diagram :  The Venn diagram is made up of two or more overlapping circles and it is used to show relationship between sets. Different sets are shown as circles in a big rectangle represent ting the universal set. Intersecting circles denote intersecting sets. Separate circles show disjoint set.                                                     

      
Venn Diagram :  The Venn diagram is made up of two or more overlapping circles and it is used to show relationship between sets. Different sets are shown as circles in a big rectangle represent ting the universal set. Intersecting circles denote intersecting sets. Separate circles show disjoint set.                                                                                                                          


Vertex, Vertices : 1. A corner of a polygon. 2. A node in a graph. 3. A local extreme point of curvature.
Vertical Line : A line which points to or away from the centre of the earth. A vertical line is perpendicular to a horizontal line.

Vertex : Point where surfaces meet-corner.
Vertical Opposite angles : The angles that are  formed when two lines intersect each other and angles  opposite to each other are equal as shown below;    A= B
                                                            A

                                                            B
Vigesimal : related to intervals of 20.
Vitali Set : A set of real numbers such that no two real numbers of the set have a difference which is rational number and each real number is equal to a rational number plus a number of the set.
Vinculum : The horizontal bar in a fraction separating the numerator from the denominator.
Volume : The measure of space occupied by a solid body.

Vulgar fraction : A common fraction.

U




T

T
Tan : Abbreviation of tangent.
Tangent
A line that meets a smooth curve at a single point and does not cut across the curve. ii) In Trigonometry, the tangent is function defined as tan x = sinx / cosx. In a right angle triangle, the tangent of an angle θ is the ratio of the length of the sides opposite and adjacent to the angle. Tan θ = Perpendicular / Base. Value of Tan varies from  0 to infinity for the angles from zero to 900
Tangent Line : The tangent line is represented a the limit of secant line.
Tangent Plane : A Tangent plane is a plane that touches a surface defined in 3dimensional coordinate system at a given point p. The normal vector of the tangent plane is perpendicular to the surface at the point p. the surface should be smooth near the  surface at the point p. the tangent plane contains all the lines tangent to a specific point on a surface.  
Tanh : Hyperbolic of tan.
Tautology : A statement of proportional logic which can be inferred from any proposition whatsoever  that is true because of its logical structure.
Taylor’s Series :  According to Taylor’s series or theorem, a polynomial f(x) can be expanded as given below around a point ‘a’ valid for an integer n .
F(x) = f(a) + f’(a) 9 x –a) + f”(a) (x – a)2 / 2! + f”’(a) (x – a)3 / 3! + ………+ fn(a) (x – a)n / n! + ……..
When a = 0 , the series is called Maclaurin series .
Tensor :  A set of quantities that obey certain transformation laws relating the bases in one generalized coordinate system to those of another and involving partial derivative sums . vectors are simple tensors.
Tera : Symbol T. A prefix having meaning 1012.
Term : A mathematical expression of the form rxn, pxnyr, where n,p,r are numbers and x and y are variable.
Terminating :To come to an end. E.g., 8.5 is a terminating decimal, while 1.733333.. is non terminating decimal.
Terminating continued fraction : A continuous fraction having finite number of terms.
Terminating decimal : A decimal that terminates is a terminating decimal. All Terminating decimal are Rational numbers but not  all rational numbers are terminating decimal expression .
Ternary number system : A number system whose base is 3.
Terrestrial triangle : The Terrestrial triangle is formed on the earth by the great circles connecting the pole and two palces on the earth.
Tessellation : A Tessellation is a repeated geometric design that covers a plane without gaps or overlaps.
Tetrahedron : A polyhedron with four faces.
Tetromino : A four-square polyomino.
THEOREM : A Theorem is a statement which is stated in natural language and can be proved on the basis explicitly states or precisely known confusions.
Theorem of Parallel axis : The moment of inertia of any object about an axis through its centre of mass is the minimum moment of inertia for an axis in that direction in space. The moment of inertia about any axis parallel to the axis is given by
Ipa  =  Icm  + Md2
Where Ipa  is moment of inertia of the body about an axis passing through centre of mass, M is the body of mass and d is the distance between the two axes.
Theoretical Probability : The chances of events happening as determined by calculating results that would occur under ideal circumstances.
Theory of Equations : Theory of equations includes the study of equations, polynomials , algebraic expressions, algebraic equations, separation of roots, approximation of roots and the application of matrices and determinants for solving the equations etc.
Theory of Games : The study of ways in which strategic interactions among rational players produce outcomes with respect of the preferences of the players, none of which might have been introduced by any one of them.
Theory of Indices : Theory of indices describes the laws for multiplication and division of quantities having same base as given below.
 1.am an  = am + n                   2am /an  = am -  n            3. (am )n  = am n                4. (ab)n  = an b n
5. (a/b)n  = an /b n              6. a0 =1                       7.   a-m =1/am                                  8. am/nm
Theory of Probability : A theory of Probability is a way of understanding probability statements. A theory of probability connects the mathematics of probability, which is the set of consequences of axioms of probability, with real world of observation and experimentation.
Therm : A unit of energy equal to 105.
Time series : Times series analysis accounts for the fact that data points taken over time may have an internal structure ( such as autocorrelation, correlation, trend or seasonal variation ) that should be accounted for the value of the variable is generated successively in time. A continuous graph trace is an example of continuous time series.
Ton : 1. Long Ton – unit of weight used in U.K., equal to 2240 lbs or 1016 kg. (2) short Ton  ; unit of weight used in U.S.A., equal to 2000 pounds or 907.18 kg. (3) Metric Ton  : usually referred to as tone equal to 1000 kg.
Topological space : A set with topology defined upon it is called a topological space .
Topology :  Generally Topology is the study of those proportions of space which are invariant under continuous deformations, that is , deformations which do not create’tears’ or ‘holes’. More specifically, given set X , a Topology on X is a collection of subsets of X, such that the empty set and X itself are included in the collection, and such that the collection is closed under the formation of finite intersection and arbitrary unions.
Torque : Symbol T, Torque about an axis is the product of force and the distance of its line of action from the axis
Toeplitz matrix : A matrix in which all the elements are the same along any diagonal that slopes from northwest to southeast.
Torus : A geometric solid in the shape of a donut.; A surface of revolution generated by revolution of a circle in three dimensional spaces about an axis passing through its centre and perpendicular to the plane of the circle and it do or not touch the circle .
Total Derivative : The rate of change of a function of two or more variables with respect to a paprameter on which these variables depend.
If Z  = f(x,y,t), x=  θ(t)   and y =  Ø(t), the total derivative of z with respect to t.
Total Differential : In analogy with the differential of a function of one variable, the total differential of a function Z = f( x,y) of more than one variable is
Dz =  dx  +   dy 
Totally ordered Set : A set with total order defined on it. An order relation on a set S is a total order exactly if, for any two elements x and y of S, either x< y , x = y or y< x , but no two of the three.
Trace : The trace of a matrix is the sum of the terms along the principal diagonal.
Transcendental Function : A function that cannot be expressed as algebraic function. E.g. , In x, sinx, ex etc., and any function containing them are Transcendental functions.
Transcendental  number : A real or complex number that is not algebraic.
Transform of Element of Group : The transform of an element ‘K’ by an element ‘X’ is X-1 is X-1 KX.
Transform of Matrix : A matrix B related to a given matrix A by the expression B = Q-1 AQ, Q being a non-singular matrix. Eigen values remain same.
Transformation : The changing of an algebraic expression or equation into an equivalent one with a different form.
Transformation of Axis : Let the coordinate of a point be (x,y,z) in a coordinate system of axes. The axis can be transformed in three ways. One , the origin is shifted keeping the axes parallel. Two , the origin is kept as it is , but the axes are rotated. Third , the origin shifting and rotation of axes take place simultaneously. The coordinate of the point with respect to new coordinate axes will be different.  
Transformation of Coordinate : A coordinate transformation is conversion from one system to another, to describe the same space. E.g. Cartesian coordinates may be converted to spherical coordinates or vice versa.
Transitive Property : The property that states that if a=b and b = c , then a =c .
Transitive relation : A binary relation R over a set X is Transitive if it holds for a,b,c in X, that is . if a is related to b and b is related to c, then a is related to c . e.g. a>b, and b>c , then a>c  ( > relation is transitive ).
Transitive Set : A set is called Transitive  if it is equal to its Transitive closure. That is, X is a Transitive set if whenever y is an element of X and z is an element of Y, then z is an element of X.
Translation :  A function which we obtain if we add the same constant to each value of the variable of the given function and move the graphs of the function by a constant distance.
Transpose: To move a term from one side of an equation to another side , with change of sign.
Transpose of Matrix : The Transpose of a matrix A is obtained by interchanging its rows and columns. It is usually denoted by AT, if A is the original matrix.
Transversal : A line that intersects two or more other lines in the same plane.
Trapezium : A quadrilateral in which no sides are parallel.
Trapezoid : A quadrilateral in which two sides are parallel.
Tree : A tree is a graph with the property that there is a unique path from any vertex to any other vertex traveling along the edges.
Triangle : A geometric figure with three sides.
Triangular number : A number of the form n(n+1)/2.
Triangular prism : A polyhedron-a prism with two identical, triangular bases.
Trinomial : An algebraic expression consisting of 3 terms.
Tromino : A three-square polyomino.
Truncated pyramid : A section of a pyramid between its base and a plane parallel to the base.
Twin primes : Two prime numbers that differ by 2. For example, 11 and 13 are twin primes.