Consider the equation below. (If an answer does not exist, enter DNE.) f(x) = 9 cos (x) - 18 sin(x), 05xs 2n (a) Find the interval on which f is increasing. (Enter your answer using interval notation.) (0 , 7 U 57 2TC 4 X Find the interval on which fis decreasing. (Enter your answer using interval notation.) 4' 4 X (b) Find the local minimum and maximum values of f. local minimum value -9V2 X local maximum value 9V2 X (c) Find the inflection points. (Order your answers from smallest to largest x, then from smallest to ( x, Y ) = 410 X 7 7 ( x, y ) = X Find the interval on which f is concave up. (Enter your answer using interval notation.) Find the interval on which fis concave down. (Enter your answer using interval notation.) Read It Watch It