4. The graph of the derivative f' of a function f(z) is shown below. (a) On what intervals is f increasing or decreasing? (b) At what values of = does f have a local maximum or minimum? () On what intervals is f concave upward or downward? You may assume an inflec- tion point occurs exactly between the two shown extrema. (d) Assuming that f(0) = 0, sketch a graph of f