Continuities of Functions

Introduction

This section is mostly the analysis of functions represented graphically. Using derivatives we find critical values. Using double derivatives we calculate inflection points.

Definitions:
Critical Value: A point on the graph of a function where either the slope is zero (f` = 0) or there is a break in the line (discontinuous).
Inflection Point: A point on the graph of a function where its curvature changes sign. This is also referred to as a change in concavity (f`` = 0).

For example:

1.1   picture

a)   Find picture
       picture

b)   Factor picture and find critical values.
       picture
       set = 0 because critical values are found when picture
       picture
       picture

c)   Give the intervals of increase and decrease.
       picture
       pick any points to test. They must be in the intervals made by the critical values.
       picture 14
       a positive picture indicates the function is increasing
       picture
       A negative picture indicates the function is decreasing
       picture
       a positive picture indicates the function is increasing
       Increasing:
       picture
       Decreasing:
       picture

d)   Give the coordinates of the relative minimum.
       picture
       The relative minimum will be the critical value which follows the interval of decrease on the graph.
       picture
       picture
       (3, -13.5)

e)   Give the coordinates of the relative maximum.
       picture
       picture
       picture
       picture