A to Z of Mathematics ( Q,R,T,V )

QED : Abbreviation for quod erat demonstrandum, used to denote the end of a proof.
Quadrangle : A closed broken figure  in the plane consisting of 4 line segments.
Quadrangular prism : A prism whose base is a quadrilateral.
Quadrangular pyramid : A pyramid whose base is a quadrilateral.
Quadrant : Any one of the four portions of the plane into which the plane is divided by the coordinate axes.                    
                                    2nd Quad        1st Quad


                                    3rd Quad        4th Quad

Quadratfrie : square free
Quadrantal angles : Any of the angles nπ /2 ( n = 0,1,2,3,4,………)
Quadratic equation   : An equation of the form f(x)=0 where f(x) is a second degree polynomial. That is,  ax2+bx+c=0.
Quadratic Expression : A function of the form f(x) = ax2+bx+c, where a  0.
Quadratic Function :  a function f(x) whose value at any value of x is given by the polynomial f(x) = ax2+bx+c. the graph of a Quadratic Function is Parabola.
Quadratic inequality : An inequality in which one side is a quadratic polynomial and the other side is zero. E.g. ax2+bx+c > 0
Quadrature : 1. The quadrature of a geometric figure is the determination of its area.               2. Quadrature means solving an integral analytically or numerically.
Quadric curve : The graph of a second degree equation in two variables.
Quadric surface : The graph of a second degree equation in three variables.
Quadrilateral : A geometric figure with four sides.
Quadrinomial : An algebraic expression consisting of 4 terms.
Quarter : indicates : one fourth = ¼ , One of the phases of moon,  one fourth of a year.
Quartic : it means fourth order. A quartic number is a number which equates the fourth power of an integer. A quartic function equated to zero results in quartic equation, that is ,                    ax4 + bx3 + cx2 + dx + e = 0 ( a  0)
Quartic polynomial : A polynomial of degree 4.
Quartic Symmetry : Symmetry in a plane figure having four axes of symmetry.
Quartile : The first quartile of a sequence of numbers is the number such that one quarter of the numbers in the sequence are less than this number.
Quintic polynomial : A polynomial of degree 5.
Quinary : Quinary is a numeral system with five as the base. In this system, five numerals from 0 to 4, are used .
Quintal : A unit for weighing mass equals to 100 kg.
Quintic Equation : An algebraic equation of 5th degree of the form ,                                          ax+ bx4 + cx3 + dx2 + ex + f = 0 ( a  0)
Quintic function : A fifth order expression of the form (ax+ bx4 + cx3 + dx2 + ex +f )(a0)
Quotient field : The set of rational numbers is afield and as any rational number is in the form a/b, where ‘a’ and ‘b’ are integers and b ≠ 0, the field of rational numbers is called quotient field.
Quotient : The number obtained by dividing one number into another.  In the division sentence:   88 divided by 11 = 8, the quotient is 8




R
Raabe’s Theorem :  This is extension of the ratio test for testing convergence of a series. The ratio test is inconclusive when the
Lim |an+1 / an | = 1 for the series .
n- α
Raabe’s test states that if  Lim |an+1 / an | = 1 and if a positive number c exists such that
                                n- α
Lim[ |an+1 / an | - 1 ] = -1- c, then the series will be absolutely convergent.
n- α


Radian
A unit of angular measurement such that there are 2 pi radians in a complete circle. One radian = 180/pi degrees. One radian is approximately 57.3o.
Radical axis : The radical axis of two circles is the  locus of points of equal power with respect to both circles.
Radical center : The radical center of three circles is the common point of intersection of the radical axes of each pair of circles.
Radical Expression : An expression in which radical sign appears and radicand is a number or expression inside the radical symbol.  represents the 3rd root .
Radical Plane : A radical Plane is the locus of the points which have equal powers with respect to two spheres S and S’. the radical plane of two given spheres is always perpendicular to the line joining the centres of the two spheres .
Radicand : Radicand is a number or expression inside the radical symbol.
Radii : Plural of radius.
Radius : The length of a straight line drawn from the center of a circle to a point on its circumference. In case of sphere , it is the distance between the centre and the surface.
Radius of Curvature : Radius of curvature of acurve at a point is the radius of the osculating circle at that point. It is also reciprocal of curvature.
Radius Vector : A vector representing the position of an object in space with respect to an arbitrary inertial frame of reference.
Radix  point : The generalization of decimal point to bases of numeration other than base 10.
Random : Having no specific pattern, purpose or objective
Random Sampling : A sampling procedure assuring that each element in the population has an equal chance of being selected.
Random Variable : A random Variable is a function that that associates a unique numerical value with every outcome of an experiment. A random Variable has either an associated probability distribution or probability density function.
Range : The set of values taken on by a function. ; The difference of the largest and the smallest value in a data collection process in a statistical experiment.
Rank : The rank of set is defined inductively as the smallest ordinal number greater than the rank of any member of the set, where the rank of empty set is zero.
Rate : A way of comparing two quantities.
Ratio : Quotient of two numbers. ; The ratio of two quantities p and q  is p/q. this is called p to q ratio.
Ratio of Simplitude : The ratio of the lengths of corresponding sides of similar figures .
Rational Expression : The quotient of two polynomials is called a rational expression. Rational expression are to polynomials what rational number are to integers.
Rational Function : A rational function is basically a division of two polynomial functions, that is , it is a polynomial divided by another polynomial. In formal notation, a rational function would be f(x)  = p(x) / q(x) , where  p(x)  and q(x)  are polynomial functions and q(x) not equal to zero .
Rational number : A rational number is a number that is the ratio of two integers. All other real numbers are said to be irrational.
Real Axis : An Axis on which only real numbers can be represented. ; The x-axis of an Argand diagram.
Real Valued Functions : A function whose range is in the real numbers is said to be real valued function.  
Real Variable :  A variable which can take only real values in the form of real numbers.
Ream : A ream is 500 sheets of paper.
Reciprocal : The reciprocal of a quantity is equal to 1 divided by the quantity itself.
Rectangle : A rectangle is a quadrilateral with 900 angles and its opposite sides are equal and parallel. The larger side is called length and smaller side is called width. Area  of rectangle is length multiply width.
Rectangular coordinates : The rectangular coordinate system is based on a grid, and every point on the plane can be identified by unique x and y coordinates. Coordinates axes are perpendicular and , hence, the coordinates on them are called rectangular coordinates. These are also called Cartesian coordinates.
Rectangular form of Complex numbers : A complex number represented in the form  ( x + iy ).
Rectangular Hyperbola :  see Hyperbola section of www.mathsdictionary.in
Rectangular Parallelepiped : A Parallelepiped with bases as rectangles, all perpendicular to its lateral faces, also known as cuboids.
Rectification :  Rectification means determining the length of an arc of a curve.
Rectilinear figure : Rectilinear figures are those which are contained by straight lines.
Recurring Decimal ; A repeating decimal e.g. 1.3333333333….
Reduction form : The reduced form of the equation
axn + bxn-1 + cxn-2 ……. = 0 is
Xn + b/a x n-1  + c/a x n-2 ………  = 0
Reduction formula in Integration : see integration section of www.mathsdictionary.in
Reduction formula in Trigonometry : see Trigonometry section of www.mathsdictionary.in
Reflection : A map that transforms an object into its mirror image.
Reflex Angle : An angle greater than 1800 but less than 3600.
Reflexive property : X= X for all X. every number equals itself.
Region : Domain, an open connected set, ; The union of such set and some or all of its boundary points.
Regression Lines : if the data is given in pairs, then the scatter diagram of the data is just the points plotted on x-y plane. The scatter plot is used to identify relationship between the first and the second entries of paired data. If points follow a linear, we can represent them by a line, called regression line.
Regular polygon : A polygon which is equiangular and equilateral .
Regular Polyhedron : A polyhedron whose faces are regular polygons all alike and is assembled in the same way around each vertex.
Relation : A property that associates two quantities in a definite order, as equality or inequality.
Relative error : There are two types of errors, that is , absolute error and relative error. Absolute error is the amount of physical error in a measurement. Relative error gives an indication of how good a measurement is relative to the size of the same thing being measured. It is ratio of error to the mean of measurement. On being multiplied by 100, we get % error.
Relative Error  = Absolute Error / Value of thing being measured
Relaxation Method : A method of solving simultaneous equations by guessing a solution and then reducing the errors that result by successive approximation until the error is less than some predefined value.
Remainder : if ‘a’ and ‘b’ are integers, with b not equal zero , then remainder is an integer r such that a = bq + r for some integer q , and with 0  
Remainder theorem : Let there be a polynomial p(x) , where “p(x)” just means that the variable in the polynomial in x. according to this theorem , if p(a) = 0, then ( x- a) is factor of the polynomial p(x) .
Repeated Root : If a polynomial f(x) is divisible by (x –a)n, then the equation f(x) = 0 supposed to have n times repeated root at x =a.
Repeating decimal : same as recurring decimal
Representative fraction :  The representative fraction is a simple ratio that informs the reader how many units of length on the actual ground surface are represented by, or contained within, the same unit of length on the map.
Residue Class : The residue classes of a function mode n are all possible values of the residue f(x) (mod n).
Residue Theorem :  It is a strong tool in complex analysis to evaluate line integrals of analytic functions over closed curves. It is also used to evaluate real integrals. It generalizes the Cauchy Integral Theorem.  For evaluating real integrals , integrand is extended to the complex  plane. A part of the real axis is extended to a closed curve by attaching a half circle in the upper or lower half plane.  We can evaluate the integral over the curve by using residue theorem.
Real part : The real number x is called the real part of the complex number  x+iy where x and y are real and i=sqrt(-1).
Real variable : A variable whose value ranges over the real numbers.
Reflective symmetry : Line symmetry means reflection. If we were to draw a line through a shape to represent a mirror, the shape could be folded along that line and both sides would both fit exactly together.
Repdigit  : An integer all of whose digits are the same.
Repeating decimal : A decimal whose digits eventually repeat.
Repunit  : An integer consisting only of 1's.
 Rhombus  : A parallelogram with four equal sides.
 Right angle : an angle formed by two perpendicular lines; a 90o angle.

Right triangle :  A triangle that contains a right angle.
Roman numerals : A system of numeration used by the ancient Romans.
Root of unity :  A solution of the equation xn=1, where n is a positive integer.
Round-off error  : The error accumulated during a calculation due to rounding intermediate results.
Rounding  :  The process of approximating a number to a nearby one.
Ruled surface  : A surface formed by moving a straight line (called the generator).

Rusty compass : A pair of compasses that are fixed open in a given position.


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/n = nth root of am
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.



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.


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