The sum of two linear functions is a linear function. But their product (when you multiply two linear functions) is a quadratic function. This activity helps you examine functions constructed by multiplying linear functions and explore how the properties of the "parents" (the linear functions) affect the properties of the "child" (the product function).


The dynamic figure below presents graphic examples of linear functions and of their product function.

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The activity helps you investigate systematically the properties of products of linear functions in various representations (graphs, value tables, and correspondence rules).



Write an essay about products of linear functions

Write a story, as complete as you can, about products of linear functions and the relations between the properties of the linear functions that are being multiplied and the properties of the product function.
  • Describe the course of your investigation and indicate your preliminary conclusions, your decisions, and mathematical justifications. What is your degree of confidence in your conclusions and decisions? Why?
  • Write also about the "Standard Product Form" and the relation between this form and "general" products of linear functions.
  • Use the tools provided to record important points for discussion and interesting or problematic cases.



  • After a preliminary investigation of the products of linear functions, you may want to turn to some of the tasks and exercises, which will help you verify and apply what you have learned and perhaps suggest other directions for investigation.












    Product of linear functions
    Product of linears - one coordinate system
    Standard product form
    Product of three linear functions


    What times what?
    Constructing product functions
    Different correspondence rules
    Factoring
    Rabbit cage
    Fencing two areas
    Optimal fencing
    Products of more than two linear functions
    Designing a box


    Exercise 1
    Exercise 2
    Exercise 3
    Exercise 4
    Exercise 5
    Exercise 6
    Exercise 7
    Exercise 8
    Exercise 9