Lesson 3.3 Functions with Line Graphs

So far we have seen that functions can take on different forms such as an equation, a table or a graph. In lessons 1 and 2 the “guess my rule” function machine metaphor helped to show the connection between the rule and the table. Lesson 3 graphing functions (more specifically, linear equations) is the focus.

As usual, Mr. Jacobs likes to present a motivational activity to start and he uses in Edition 3 the story about Robert Wadlow who at one time was the tallest man in the world to show the relationship between age and height. There is a marvelous website about Mr. Wadlow at http://www.altonweb.com/history/wadlow/ which is a fascinating read.

Note: The word rule is used interchangeably with equation and even sometimes with function. This can cause confusion because a rule doesn’t always have to be an equation and not all equations are necessarily functions depending on how it’s defined. For example a mathematical rule (which is what we are talking about here) could be an inequality like y > 3. Functions in higher math can become very complex so I tend to avoid using the term especially with younger students.

Let me know if you have any problems with Sets I and II. His Set III questions are usually a bit more challenging (and interesting), so you can skip them if you feel it would be appropriate.

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