# Math Vocabulary - E

Word Definition Examples
Element
1. Each object or number in a set
2. Each entry in a matrix

Visit Math is Fun for a great explaination of sets. Elimination Using addition or subtraction to eliminate one variable when solving a system of equations.

Purple Math has a simple explaination, and Math Planet shows a more difficult explaination.

End behavior The way a graph of an equation behaves at the far left and right ends as the input variable goes to positive or negative infinity +

For the cubic equation graphed here, at the left end (very negative) the graph goes down to negative infinity. The right side (very big positive) the graph goes up to positive infinity. Epsilon Ε ε Greek letter used in math problems.

In Calculus, the small epsilon is used to represent very small positive numbers. Equation Two expressions that are equal. Uses the = sign to show the relationship that two things are equal to each other.
Each side of the equation is an expression.
x + 2 = 7

4x2 + 2x = 7

Equiangular polygon A polygon where all the angles are congruent

All angles are equal, but the size of the angles depends on the number of sides in the polygon Equiangular triangle A triangle where all the angles are congruent

All angles are equal and, because it is a triangle, they must equal 60 degrees. Equilateral polygon A polygon where all the sides are congruent.

All sides are the same length (equal in length).  Equilateral triangle A triangle where all the sides are congruent - all sides are equal.

Note: an equilateral triangle is also equiangular! Euler Line In geometry, the centroid, circumcenter and orthocenter of any triangle always lie on a straight line, called the Euler line. Click here to see an animated example of the Euler line.
Even function A function graph whose axis of symmetry is the y-axis.

f(x) = f(-x) Even number Any number that can be divided by 2 with no remainder. In Algebra, 2n can represent any even number.
Event In probability, any group of outcomes The possible results When rolling one dice, the outcomes are 1, 2, 3, 4, 5, or 6
Exact number Am number that is the result of counting or the results from a theoretical calculation. Measurements are not exact numbers.
Experimental data In statistics, data that collected from an experiment set up specifically to answer a question.
Experimental probability In probability, the ratio of the number of times an event happens to the number of times the experiment is done Results from doing an experiment P(event) = times it happened ÷ times you tried
Exponent A raised number that represents repeated multiplication of a factor 34 = 3 • 3 • 3 • 3
Exponential decay An equation used to calculate how things get smaller over time - used for radioative decay and age dating. y = C(1 - r)t
where y is the final amount, C is the original amount, r is the rate of change, and t is time.
Exponential function An equation of the form y = bx where there is a variable as an exponent. Exponential functions are the inverse of logarithms Exponential growth An equation used to calculate how things increase over time - used for growth of bacteria and other populations. y = C(1 + r)t
where y is the final amount, C is the original amount, r is the rate of change, and t is time.
Expression Any combination of values and operations (no = sign) 4x2 + 2x
Exterior angle In a polygon, the angle formed by a side and an extension of a side. Extraneous Solution A number that comes when you solve an equation, but it doesn't work in the original equation. Frequently occurs in equations that have a variable under a square root sign.
Comments, questions, or you just need some help? Send an e-mail to Mrs. Shearer Last Updated: 06/26/2014
© K. A. Shearer 2005-2014

Buttons created at ButtonGenerator.com.