Q4 (20 points) Find the intervals on which f(x) = 2x3 + 3x2 -36x is increasing or decreasing, and find local extrema of f (x) . Find the intervals on which f(x) =2x* +3x2 -36x is concave upward or concave downward, and find the inflection point of f(x).Q5 (20 points) Use the graph-sketching scheme given in lecture week 6 to sketch the graph of f( x ) - x -4 *. Carefully indicate domain, intercepts, symmetry, asymptotes, x2 +4 derivatives, critical points, local extrema, and inflection points