Graph of the product of two functions
- Enter the two linear functions in as Y1 and Y2. 
 
  - Move the cursor to enter a function for Y3.
 
  - Use the VARS key and cursor over to Y-VARS.
 
  - Move the cursor to 1:Function and press ENTER.
 
  - Choose 1:Y1 and ENTER. Y1 will appear as the first part of function Y3.
 
  - Hit the multiplication key and repeat to enter Y2. 
 
  - The screen will read Y3 = Y1 x Y2. Graph the new function.