13.1: Inverse Variation
This activity is intended to supplement Algebra I, Chapter 12, Lesson 1.
Part 1  Enter the Data
Enter the data from the table into lists.
Press STAT ENTER. Enter the



1 

2 

3 

4 

5 

6 

Press
Press ENTER to turn the plot On. Select scatter as the type of plot,
Press WINDOW. Set the window to the following:
Press GRAPH.
Part 2  Questions
 How would you describe the relationship between
x andy by examining this data?
Press STAT ENTER to return to the lists.
 What relationships can you see by examining the numbers in the lists?
 What is the product of each pair of numbers?
Arrow to the top of
Press ENTER to execute the formula. The product in each case is
 What type of situation might this be a formula for?
Solve the equation
 What is your equation?
Press GRAPH.
 What other information can you find from the graph of the equation that you could not gather from the plot?
 Does this graph appear to be a function? Explain.
Press
 What is happening when
x=0 ? Why?
Arrow up to the negative
 What do you notice about the
y− values?  Why does this occur?
 What do you think the graph of your equation looks like to the left of the
y− axis?
Press WINDOW. Set the window as shown to examine the graph when
Press GRAPH.
 What appears to be happening when
x=0 ?  Why does the graph of the equation not appear in Quadrants II or IV?
 Do you think an inverse variation can ever be found in Quadrants II or IV? Why?
 Does this graph appear to be a function now? Explain.