The derivative

Here we present an applet that shows the graph of an "abstract" function f(x). The user can visit all the points of the graph by modifying the value of a, and he or she may observe the behaviour of the tangent line to the graph and the value of the derivative.

On this example a student may be asked to search the maxima and minima by looking for those values of a for which the derivative f´(a) vanishes, that is, f´(a)=0.

This example uses he tool VARIABLES to define a very small real number dx which is used to aproximate the derivative. It also uses the tool FUNCTIONS to define a function f(x) which is used to illustrate the concepts of derivative and tangent line to the graph without showing an explicit expression for the function that would distract the student's attention from the main concepts.

The reader should notice that a special configuration feature of EQUATIONS is used for the tanget line. Descartes it is explicitely instructed to hide the expression of the equation of the tangent line. This is done by adding the statement VISIBLE=false to its configuration.

Introduction  Appetizer  Examples  Documentation  Applications  Work plan

	Ministerio de Educación, Cultura y Deporte. Año 2000