Goal: Identify and graph functions.

 Relation: mapping or pairing, of input values with output values.  Domain: Set of input values.  Range: set of output values.  Function: a relation is a function if each input value has exactly one output.

 Identify the domain and range. Then tell whether the relation is a function. Explain.

 Graph the relations from Ex. 1. Use the vertical line test to tell whether the relation is a function.

 A. graph the relation shown in the diagram below.  B. Explain how to use the vertical line test to show whether the relation is a function.

 Equations in two variables: such as y = 5x – 2; an ordered pair (x, y) is a solution of such an equation if substituting the values of x and y into the equation makes a true statement.  Independent variable: the input variable in an equation.  Dependent variable: the output variable.

 Graph y = x + 1

 y = x - 3

 y = -x + 4

 y = 2x + 3

p. 70 – – 46 even, 52-56