Calculus
Lesson
15 Concavity
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Concave up if is increasing.
Concave down if is decreasing.
Concavity changes at points of inflection!!!!
Since rate of change of is ,
indicates that is concave up at .
indicates that is concave down at .
indicates a possible point of inflection at .
Note that it doesn always mean that there is a point of inflections.
Example:
We must use a sign chart to make sure that changes sign.
If does not change sign, then is not a point of inflection.
For each of f, g, and h, identify all critical points and all points of inflection.
Same Examples as last lesson:
Note: never equals zero, so there are no points of inflection!
Also:
Test to see if they are points of inflection!
If , then the test is inconclusive - you can always use the
first derivative test!
Example: