Letf(x) = (x + 1)^2(x-2).
(a) Find the maximum and minimum values of f(x);
(b) A point of inflection is a point where the graph changes direction of
concavity, i.e. a point where f''(x) = 0. Find the inection point(s) of
f, and determine where the function is concave up and concave down