4. The graph of the derivative of a function f is shown below. Answer the following questions about f. Explain your answers for full credit. y = f' ( x ) -2 O 4 2 4 (a) (4 points) On what intervals is f increasing/decreasing? (b) (4 points) What are the critical points of f? X = 1 , 6, 8 (c) (3 points) For what values of a does f have a local maximum or minimum? Indicate which is whic (d) (4 points) On what intervals is f concave up/concave down? (e) (3 points) For what values of a does f have an inflection point? X-2, 5,7