Math Glossary Letter E
earnings before interest and taxes
Earnings Before Interest and Taxes

Revenue - Operating Expenses
EBIT
Earnings Before Interest and Taxes

Revenue - Operating Expenses
eccentricity
Deviation of a conic from a circular shape
economics
study of production, distribution, and consumption of goods and services
edges
line segment joining two vertices
effective annual yield rate
Yield rate taking compounding periods into effect
eigenvalue
set of scalars associated with a linear system of equations
elapsed time
Amount of time between two dates
elimination
Eliminating a variable in a system of equations to solve for another variable or variables
elimination method
Eliminating a variable in a system of equations to solve for another variable or variables
ellipse
a regular oval shape, traced by a point moving in a plane so that the sum of its distances from two other points (the foci) is constant
empirical rule
Provides estimate for the spread of data in a normal distribution. 68% of the data will fall within one standard deviation of the mean. 95% of the data will fall within two standard deviations of the mean. 99.7% of the data will fall within three standard deviations of the mean
empty set
The set with no elements

encryption
encoding a message such that anybody outside authorized parties cannot read it
endpoint
end of a ray, line segment, or interval
energy
property that must be transferred to an object in order to perform work on
engineering
the application of science and mathematics by which the properties of matter and the sources of energy in nature are made useful to people
entropy
refers to disorder or uncertainty
equated time
determine time from cash flow streams
equation
a statement declaring two mathematical expressions are equal
equation of a circle
formula to graph a circle and the points on the circle

(x - h)2 + (y - k)2 = r2
equation of a line
formula to graph the points on a line

y = mx + b
equation of a plane
formula to graph the points in a plane

Ax + By + Cz + D = 0
equation of exchange
equation relating money, price, velocity, and quantity

MV = PQ
equilateral triangle
A triangle with 3 equal sides
equivalent annual cost
formula comparing two different projects to see which one is more valuable
equivalent coordinates
Relating cartesian and polar coordinates
equivalent expressions
see equations
equivalent fractions
Two fractions with equal values, using a common factor to scale the numerator and denominator
estimate sum
Using rounding to estimate the total of numbers using their rounded figures
estimation
rough calculation of a number or quantity
euclidean norm
magnitude or length of a vector
euclids algorithm
method for computing the greatest common divisor (GCD) of two numbers
euclids extended algorithm
division algorithm for integers
euler
Famous mathematician who developed Euler's constant
Euler's Formula
Equation relating 5 mathematical constants

e + 1 = 0
Eulers Constant
limiting difference between a harmonic series and natural logarithm

0.5772156649
eulers totient
the number of positive integers that are relatively prime to
even numbers
Numbers divisible by 2
evil numbers
A number with an even number of 1s in the binary expansion
exabyte
multiple of the unit byte for digital information
exact time
excel
A spreadsheet software
exchange matrix
row-reversedr or column-reversed version of the identity matrix
exchange rate
The rate to convert one unit of currency to another unit of currency
expand polynomials
Write out the multiplication of polynomials term by term
expanded notation
Writing out a number to show the sum of each digit multiplied by the place value

9256 = 9(1000) + 2(100) + 5(10) + 6(1)
expected frequency
counts calculated using probability theory
expected return
amount of profit or loss an investor anticipates on an investment
expected value
predicted value of a variable or event
experiment
In statistics, a controlled and repeatable process
exponent
The power to raise a number
exponential distribution
probability distribution that describes the time between events in a Poisson point process
exponential fit
Fit a curve to a set of data using an exponential function
exponential growth
growth whose rate increase in proportion to the total number
exponential identity
Identity using exponents for equivalent expressions
exponential smoothing
Create smoothed data using exponential functions
exports
goods and services produced in one country and purchased by citizens of another country
expression
finite combination of symbols