ECO 315 Quiz 2

Cartesian Plane

a plane where an x-axis and a y-axis cross at a right angle; allows for the mapping (placement) of ordered pairs

Cartesian Product

x x y (read; “x cross y”); a mapping of unordered pairs into ordered pairs

Single-Variable Functions

exist in 2-dimensional space in which the dependent variable is a function of a single independent variable

Plane

a Cartesian product of ordered sets of two

Surface

a Cartesian product of ordered sets of three

Hypersurface

a Cartesian product of ordered sets of four

Multivariable Functions

exist in 3-dimensional or higher space in which the dependent variable is a function of two or more independent variables

Relation

given an x value, one or more y values can be specified

Function

a relation in which each x value corresponds to one and only one y value

Polynomial Function

a function in which each term of the equation contains a coefficient as well as a nonnegative-integer power (an exponent) of the independent variables; have both an intercept and a slope

Degree of a Polynomial

highest exponent

Rational Function

a function that is expressed as a ratio of two polynomials

Non-Algebraic Function (Transcendental Functions)

any function not expressed in terms of polynomials and/or roots of polynomials

Trigonometric Function

circular mapping function

Exponential Function

independent variable appears as an exponent

Logarithmic Function

inverse exponential functions

Equation

a specific declaration of a relation or function (the relational or functional form)

Definitional Equation

an identity between two alternative expressions that have exactly the same meaning

Behavioral Equation

specifies the manner in which a variable behaves in response to changes in other variables

Equilibrium Condition

describes the prerequisites for the attainment of equilibrium

Elements of an Equation

Variable, Constant, Coefficient, and Parameter

Variable

something whose magnitude can change

Endogenous Variable

originates within model (choice variable)

Exogenous Variable

variables that are held constant than can impact results of the model (outside of the model)

Reduced Form Equation

an equation that expresses all the endogenous variables in an equation in terms of the exogenous variables

Constant

something whose magnitude does not change

Coefficient

constant joined to variable

Parameter

constant that is a variable

Inverse Equations

reverses action of another equation