Identifying Functions King/Halling Algebra 2011-2012

AIM What is a vertical line test and how can we use it to determine if a given relation is a function?

DO NOW Read through the Test Corrections guidelines sheet while you wait for your quiz. When you get your quiz back, look over the mistakes you made and be ready for further instructions.

Quick Check In 3-4 sentences, explain what a function is and what it does. You must use at least 3 of the vocabulary words that you learned in class yesterday in your definition.

Graphing Data The following is the data table from Machine #2 As an ordered pair, this point is written as (0,4) Input Output -4 -1 3 4 2 6 7 Domain (x value) Range (y value)

Plotting Points On their own number lines, these points would be plotted: Domain (x) Range (y)

Instead, we graph these points together on a coordinate plane to illustrate their relationship Output/Range Input/Domain

Graphing a Function Use the grid to the left to plot all of the ordered pairs generated by Machine #2. Connect the points Use 1 term from your vocab sheet to define this function

The Vertical Line Test One way to use the graph to check if a relation is a function is the vertical line test You imagine a vertical line being drawn through the graph. If the vertical line only touches the graph at one point, then it is a function.

More Practice Is the relation graphed at the right a function? Unless asked, you really don't need to draw the vertical lines. You can imagine them, or I have my students use the edge of a sheet of paper and move it across the graph.

Exit Ticket Use the vertical line test to tell whether or not the following graphs are functions. a) b) c)

Homework Homework 9: Pg.259-260 #21-23, 32-35