In the work for problems 1 (a-b), 2. and 3 (ab) it is expected that you will clearly show ALL of the following: 1) The number lines representing the appropriate derivative(s) for the problem. 2) Any test values that you are using. 3) Either the full calculations andfor sign charts that you are using to establish the signs of the derivatives. Simply recording what the signs on the number line are without supporting work is NOT enough and voids any answers given to the problem regardless of whether they are correct or not. 3) For each of the following, determine the intervals on which the following functions are concave up and concave down. a) f(x) = =x4 -8x3 -144x2 + 32x