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 ![]()
a) Find ![]()
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b) Factor
and find critical values.
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set = 0 because critical values are found when ![]()
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c) Give the intervals of increase and decrease.
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pick any points to test. They must be in the intervals made by the critical values.
14
a positive
indicates the function is increasing
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A negative
indicates the function is decreasing
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a positive
indicates the function is increasing
Increasing:
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Decreasing:
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d) Give the coordinates of the relative minimum.
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The relative minimum will be the critical value which follows the interval of decrease on the graph.
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(3, -13.5)
e) Give the coordinates of the relative maximum.
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