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: 

 

On to Lesson 16 - Limits at Infinity

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