Consider the equation below. f(x) = 4x^3 + 18x^2 − 216x + 1 (a) find the intervals on which f is increasing. find the interval on which f is decreasing. (b) find the local minimum and maximum values of f. (c) find the inflection point. find the interval on which f is concave up. (enter your answer using interval notation.) find the interval on which f is concave down. (enter your answer using interval notation.)