I. Definitions:

 

A function is increasing on an interval I if    x1 <x2  =>  F(x1)<F(x2)    for any x1, x2 in I.

 


A function is decreasing on an interval I if ______________________for any x1, x2 in I.

 

A function is concave up on an interval I if, over that interval, the graph:
 

·         “curves upwards”

·         a line segment connecting any two points lies above the graph

·         any tangent lies below the graph

 


A function is concave down on an interval I if:

·          

·          

·          

 

An inflection point is a point on the graph of a function where the function is continuous and

changes concavity.

 

 

II. What do derivatives tell you about the shape of the graph of a function F(x)?

 

  1. First derivative (=slopes of the graph) determines:

 

    1. The sign of the first derivative tells if the function is increasing or decreasing:

                                                              i.      F’(c)>0 means that F is ____________________at c.

                                                            ii.      F’(c)<0 means that F is ____________________ at c.

    1. F’(c)=0 (or F’(c) undefined) means that c is a critical point for F

 

  1. Second Derivative (=how the slopes are changing) determines:

 

    1. The sign of the second derivative tells the concavity of the graph

                                                              i.      F’’(c)>0 means that the function is concave up J (because the slopes are increasing)

                                                            ii.      F’’(c)<0 means that the function is concave down L (because _______________________________)

    1. F’’(c)=0 means that either c is a critical point, or it’s an inflection point.