Ultramarathon Pacing and Rational Functions

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Objective

SWBAT investigate properties of rational functions.

Big Idea

Use an ultramarathon pacing scenario to make sense of rational functions and asymptotes.

Quick Quiz

25 minutes

Today we start class by taking a Quick Quiz (Quick Quiz - Polynomial Functions) to go over some of the important concepts of polynomial functions. We spent the last four days studying these functions, so I want a quick formative assessment before we move on to rational functions. This gives students a gauge of how well they understand the concepts before we take our test at the end of the unit. I am not allowing graphing calculators for this particular quiz because I want to assess their conceptual understanding, not their ability to use their graphing calculator. Both are important skills and I will assess both on the unit test.

Explore

25 minutes

After the quiz, this task is a great way to get students thinking about rational functions. Specifically, this task does a nice job of introducing a context where asymptotes make a lot of sense. My inspiration for this task was my daily warm-up on the treadmill at my gym; I always ran the first minute slower than the remaining portion of the run and I would always picture this graph in my mind. Sometimes you just can't turn the math off! (I recommend completing the task on your own before giving it to your students.)

Give students the worksheet and have them work on it with their groups for about 20 minutes. It is straightforward enough that they should have no problems working through the first five problems. Writing the equation and graphing may be a little more challenging. The last two Mathematical Practices (MP7 and MP8) should come in handy as they are using the structure and repeated reasoning for the first five questions to come up with a generalization to find the average pace at mile x. If they get stuck, remind them to look at the structure of how they came up with the first five answers.

5 minutes