Difference Quotients

Difference quotients are the path to the definition of the derivative. Here are three posts exploring difference quotients. Difference Quotients I  The forward and backward difference quotients Difference Quotients II      The symmetric difference quotient and seeing the three difference quotients in action.  Showing that the three difference quotients converge to the same value. Seeing Difference…

Working up to the derivative.

While limit is what makes all of the calculus work, people usually think of calculus as starting with the derivative. The first problem in calculus is finding the slope of a line tangent to a graph at a point and then writing the equation of that tangent line. Local Linearity is the graphical manifestation of…

Seeing Difference Quotients

Third in the graphing calculator series.  In working up to the definition of the derivative you probably mention difference quotients. They are The forward difference quotient (FDQ):  The backwards difference quotient (BDQ): , and The symmetric difference quotient (SDQ):  Each of these is the slope of a (different) secant line and the limit of each as…

Discovering the Derivative

Discovering the Derivative with a Graphing Calculator This is an outline of how to introduce the idea that the slope of the line tangent to a graph can be found, or at least approximated, by finding the slope of a line through two very close points in the graph.  It is a set of graphing calculator…

The Derivative II

(In this activity I am paraphrasing and expanding the suggestions of Alan Lipp in a posting “Derivatives of Trig Functions” August 29, 2012 to the Calculus Electronic Discussion Group.) This activity parallels the one in my last post here using technology. Enter the function you are investigating as Y1 in your calculator. Later you will…

The Derivative I

In “Local Linearity II”, my post for August 31, 2012, we developed a way of approximating  the slope of a function at any point. The slope at x = a is approximated by For small values of h. The smaller the better which suggests limits. The limit of this expression as h approaches zero is…