ALGEBRA GLOSSARY
Mr. X is glad to provide video presentations of hundreds of algebra glossary terms. The algebra glossary is part of a complete math glossary available free of charge on the website. All algebra glossary terms are provided free of charge to all users. Registering with the site for a free account gives access to our search tools. Subscribers to our service can gain additional access to video presentations of algebra lessons and sample algebra problems and solutions. Register or subscribe today and allow Mr. X to help you master the language of mathematics!A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Title  Description  

Decreasing  Decreasing means to lessen in extent or scope, to be reduced. A function is considered to be Decreasing if the values in the range decrease as the values from the domain increase. 

Deductive Logic  Deductive Logic is employed before events have transpired, before the fact.  
Degree, Polynomial  The Degree of a polynomial is the order, or highest power (term) of the polynomial.  
Delta  Delta is the fourth letter of the Greek alphabet. Uppercase Delta looks like a triangle and is used to mean "the change in..." 

Denominator  The Denominator of a fraction is the number on the bottom; it is the divisor of the numerator.  
Dependent Variable  If y = f(x), then y is a function of x and y is the Dependent Variable. Think of it this way: whatever we get for output "y" depends on the input "x" we grab from the domain of the function. 

Determinant  A Determinant is a number associated with a square matrix. It may also be a cofactor, a number associated with a square array from a larger matrix. 

Diagonal Matrix  A square matrix with zero values everywhere except on the main diagonal (upper left to lower right) is termed a Diagonal Matrix.  
Dimension, Matrix  The Dimension of a matrix is its order, or size. We label the order of a matrix by its number of rows then its number of columns. A 4x3 matrix is read as "a four by three matrix" and has four rows and three columns. 

Direct Proportion  When variables are in Direct Proportion to one another they have the relation that as one variable grows the other either increases or decreases by a constant multiplication factor. When y = kx, we say the variables are in Direct Proportion. 

Direct Variation  Also direct proportion, Direct Variation describes the relation y = kx.  
Discontinuity  When a function is literally not continuous because of a gap, a step, a hole, or any kind of "break" it is considered discontinuous.  
Discrete Function  When the inputs from the domain of the function are not smooth and continuous but rather incremental, the function is considered to be a Discrete Function.  
Discriminant  In the Quadratic Formula, the radicand (the business inside the squareroot sign) is the Discriminant. In general, a Discriminant provides algebraic information about the roots of polynomials. 

Disjoint  Disjoint sets have no common elements.  
Distance Formula  The familiar Distance Formula in Cartesian (rectangular) coordinates is a version of the Pythagorean Theorem, where the sum of the squares of the legs of a right triangle is equal to the square of the hypotenuse.  
Distributive Property  The familiar Distance Formula in Cartesian (rectangular) coordinates is a version of the Pythagorean Theorem, where the sum of the squares of the legs of a right triangle is equal to the square of the hypotenuse.  
Divergent Geometric Progression  An infinite geometric progression (or a significant portion of one) is termed Divergent when its common ratio has an absolute value less than or equal to 1, or greater than or equal to 1.  
Domain  The values that are "legal" and "legitimate" to put into a function are the elements of the Domain of that function. When y = f(x), the legitimate values of x are the Domain of the function. 

Dot Product  A product of vector multiplication, the Dot Product is a scalar, which means it has magnitude only and not an associated direction. The Dot Product does not result in another vector. 

Doubling Time  The time it takes an exponential or geometric growth to double in size (grow by 100 percent of the original value) is its doubling time. 
Please send us an email with your suggestions for this glossary. We at Mr. X want this site to be as helpful as possible.