b Set the first derivative f x 0 to find any critical values Tip You may wish to graph f x by itself to explore if it has any zeros It can be helpful to know that the formula of f x factors Select the correct choice below and if necessary fill in the answer boxes within your choice A The function f has a critical number at x 1 3 at this critical number the second derivative f x 0 Type an exact answer OB There are no critical numbers c What conclusion can be made from your answer to part b Select the correct choice below and if necessary fill in the answer box within your choice OA At the critical number x OB At the critical number x OC At the critical number x D At the critical number x E No conclusion can be made using the second derivative test at this critical number O the function f is concave down and corresponds to a relative minimum of f x the function f is concave down and corresponds to a relative maximum of f x the function f is concave up and corresponds to a relative maximum of f x the function f is concave up and corresponds to a relative minimum of f x d Set the formula for the derivative f x 0 to find any possible inflection points 1 3 f x 0 at x Use the table feature for the graph of f x to examine the concavity of the graph of f x What can you conclude Select the correct choice below and if necessary fill in the answer boxes within your choice OA There is a point of inflection at x B There is a point of inflection at x down to where the graph of f changes from concave down to concave up The slope of the graph of f at this inflection point is where the graph off changes from concave up to concave down The slope of the graph of f at this inflection point is