Daily compounding
In the compound interest formula, it is when n = 365 (exact
interest) or when n = 360 (ordinary interest). In this book,
use ordinary interest unless otherwise indicated.
Data processing
The recording and handling of information by means of mechanical
or electronic equipment.
Database A collection
of information. A data-base manager is a program that is
in charge of the information stored in a database.
Database manager
A computer program that allows a user to interface with
a database.
Dealer's cost
The actual amount that a dealer pays for the goods sold.
Debug The organized
process of testing for, locating, and correcting errors
within a program.
Decagon A polygon
having ten sides.
Decay formula
Deci- A prefix
that means 1/10.
Decibel
Deciles Nine
values that divide a data set into ten equal parts.
Decimal Any number
written in decimal notation. The digits represent powers
of ten with whole numbers and fractions being separated
by a period, called a decimal point. Sometimes called a
Hindu-Arabic numeral.
Decimal fraction
Decimal notation
The representation of a number using the decimal number
system. See Decimal.
Decimal
numeration system A numeration system with base
10.
Decimal point
See Decimal.
Decisiveness
Given any set of individual rankings, the method produces
a winner when voting.
Decoding key
A key that allows one to unscramble a coded message.
Deductive
reasoning A formal structure based on a set of axioms
and a set of undefined terms. New terms are defined in terms
of the given undefined terms and new statements, or theorems,
are derived from the axioms by proof.
Definite integral
Degree (1) The
degree of a term in one variable is the exponent of the
variable, or it is the sum of the exponents of the variables
if there are more than one. The degree of a polynomial is
the degree of its highest-degree term. (2) A unit of measurement
of an angle that is equal to 1/360 of a revolution.
Deka- A prefix
that means 10.
Deleted point
A single point that is excluded from the domain.
De Morgan's laws
Demand The number
of items that can be sold at a given price.
Denominator
See Rational number.
Dense set A
set of numbers with the property that between any two points
of the set, there exists another point in the set that is
between the two given points.
Denying
the antecedent A logical fallacy; same as the Fallacy
of the inverse.
Denying
the consequent Same as indirect reasoning.
Dependent events
Two events are dependent if the occurrence of one influences
the occurrence of the other.
Dependent system
If every ordered pair satisfying one equation in a system
of equations also satisfies every other equation of the
given system, then we describe the system as dependent.
Dependent
variable The variable associated with the second
component of an ordered pair.
Derivative
Description
method A method of defining a set by describing
the set (as opposed to listing its elements).
Descriptive
statistics Statistics which is concerned with the
accumulation of data, measures of central tendency, and
dispersion.
Diagonal form
A matrix with the terms arranged on a diagonal, from upper
left to lower right and zeros elsewhere.
Diameter See
Circle.
Dice Plural for
the word die, which is a small, marked cube used in games
of chance.
Dictatorship
A selection process where one person alone makes a decision.
Die See Dice.
Difference
The result of a subtraction.
Difference
quotient
Difference
of squares
Differentiable
function See Derivative.
Differential
calculus That branch of calculus that deals with
the derivative and applications of the derivative.
Dimension A
configuration having length only is said to be of one dimension;
area and not volume, two dimensions; volume, three dimensions.
In reference to matrices, it is the numbers of rows and
columns.
Direct reasoning
Directrix See
Parabola.
Discount A
reduction from a usual or list price.
Discrete
mathematics That part of mathematics that deals
with sets of objects that can be counted or processes that
consist of a sequence of individual steps.
Disjoint sets
Sets that have no elements in common.
Disjunction
The disjunction of two simple statements p and q
is false whenever both p and q are false,
and is true otherwise. The common translation of conjunction
is "or."
Disk drive
A mechanical device that uses the rotating surface of a
magnetic disk for the high-speed transfer and storage of
data.
Distinguishable
permutation
Distributive
laws of exponents
Distributive
property (for multiplication over addition) If a,
b, and c are real numbers, then a(b
+ c) = ab + ac and (a + b)c
= ac + bc for the basic operations.
That is, the number outside the parentheses indicating a
sum or difference is distributed to each of the numbers
inside the parentheses.
Diverge A sequence
that does not converge is said to diverge.
Dividend The
number or quantity to be divided. In a/b, the dividend
is a .
Divides See Divisibility.
Divine proportion
If two lengths h and w satisfy the proportion
h/w = w/(h + w)
then the lengths are said to be in a divide proportion.
Divisibility
If M and d are counting numbers and if there
is a counting number k so that m = dk, we
say that d is a divisor of M, d is
a factor of M, d divides M, and M
is a multiple of d.
Division
a/b = x is a divided by b equal
to x and it means a = bx.
Division by zero
In the definition of division, (b not equal to 0),
because if b = 0, then bx = 0, regardless
of the value of x. If a is not equal to zero,
then there is no such number. On the other hand, if
a = 0, then 0/0 = 1 checks from the definition, and
so also does 0/0 = 2, which means that
1 = 2, another contradiction. Thus, division by 0
is excluded.
Division of integers
The quotient of two integers is the quotient of the absolute
values, and is positive if the given integers have the same
sign, and negative if the given numbers have opposite signs.
Furthermore, division by zero is not possible and division
into 0 gives the answer 0.
Division
of rational numbers
Division
property (of equations) The solution of an equation
is unchanged by dividing both sides of the equation by the
same nonzero number.
Division
property of inequality See Multiplication property
of inequality.
Divisor The quantity
by which the dividend is to be divided. In a/b, b
is the divisor.
Dodecagon A
polygon with 12 sides.
Domain The domain
of a variable is the set of replacements for the variable.
The domain of a graph of an equation with two variables
x and y is the set of permissible real-number
replacements for x .
DOS
Disk Operating System the set of programs that allows
both the user and the computer to communicate with a disk
drive. The manufacturer is Microsoft, so sometimes it is
referred to as MS DOS.
Dot matrix
printer A type of printer that forms letters using
tiny dots, usually 9 or 24 (for better quality) dots per
letter.
Double negative
- (- a) = a
Double subscripts
Two subscripts on a variable as in x12
(Read this a x sub one two and not sub twelve.)
Down payment
An amount paid at the time a product is financed. The purchase
price minus the down payment is equal to the amount financed.
Download
To copy a program from the network to your computer.
Dummy variable
A variable in a mathematical expression whose only function
is as a placeholder.
