Most likely, every formula you have ever used is a function.  For example, finding out how much money you make:  Your hours worked is your input, the earnings is your output, and there is a formula or rule that converts the input into output.

Today, we will see how a function is different from a relation, and how we use notation that makes it more clear what the input and output is.

Things you should know after today:

  • definition of a function
  • the vertical line test
  • how input and output are related to (x,y) coordinates
  • What f(3) means.
  • How to determine f(3) from a graph and from an equation
  • How to determine x if you know f(x) = something



  • p311 #1-8, 10, 11, 14 *12 *15
  • Extra practice #, 2, 4, 7-9