# Change!

## Objective

SWBAT calculate the average rate of change of a function over a specified interval. SWBAT interpret the average rate of change of a function over a specified interval.

#### Big Idea

Just what does that change mean? Your students build understanding of rate of change as they calculate then interpret their work for each other.

## Set the Stage

5 minutes

I begin this lesson with the same function on the board that we began with yesterday:

f(x) = 0.2x^2.

This time I ask my students to work with their back partner to determine the rate of change for this function without specifying which section of the graph to consider. (MP1) I do this intentionally to see how my students handle this, because it should be review from previous classes.  After a few minutes or when discussion dies down, I ask for volunteers to post their solutions on the board.  We critique any solutions posted, with a focus on whether they fit for the whole function. (MP3) This allows my students to realize that some functions do not have a single rate of change on their own, instead of just hearing it from me.

45 minutes