Whitman College: David Guichard's "Calculus, Chapter 2: Instantaneous Rate of Change: The Derivative, Section 2.1: The Slope of a Function"

Read Section 2.1 (pages 29-33). You will be introduced to the notion of a derivative through studying a specific example. The example will also reveal the necessity of having a precise definition for the limit of a function.

Click https://s3.amazonaws.com/saylordotorg-resources/wwwresources/site/wp-content/uploads/2012/07/calculus_02_Instantaneous_Rate_of_Change-_The_Derivative.pdf link to open resource.