This activity focuses on functions that are piecewise linear, like the graphs generated below:



Many phenomena cannot be described by a single linear function, but can be described by functions that are linear over intervals. For example:
A group of bikers rode at a high speed during the first part of a trip, then continued at a slower pace.
  • By law, after 8 hours of work per day, every hour is considered overtime; employers must pay at least 25% more for the first two hours of overtime and at least 50% more for additional hours.
  • The Flash cellular phone company charges 5 cents per minute during the day and 2 cents per minute after 8 pm.

  • Use the Functions on intervals tool in the general tools list or the Piecewise linear functions tool to construct functions that describe phenomena of this type.


    Investigate a real-life phenomenon that can be described using functions on intervals

    Consider real-life phenomena that can be described (exactly or approximately) using functions on intervals.
  • Choose such a phenomenon and collect the relevant data (by measurements, or from papers, books, or the Internet).
  • Construct appropriate functions, raise questions that come naturally with regard to the phenomena you are describing, and explain whether and how these questions can be answered using various representations of your functions.








  • Piecewise linear functions

    Journeys at two speeds
    Planning a trip
    Stories about journeys
    Trips and reflections
    Overtime
    Coupons
    Mobile phone rates
    Income tax (I)
    Income Tax (II)