18. Assume f is differentiable on the interval (0,5). The table shown here gives the value of f, f', and f" for several values of x. Which value of x must produce a local maximum ? x 1 x = 2 X=3 f(x ) 0 0 f' (x) 5 0 0 f" (x) 5 0 1-2 0 [A] x - 2 [B] x =1 [C] x =4 [D] x -3 [E] There is no local maximum. 19. The second derivative of a differentiable function f is given by f" (x) = x2-1 Identify the x-value(s) of all inflection point(s) for the function f. [A] 0 only [B] 1 only [C] -1and 1\\\\ [D] : 1, 0,and 1 \\[E] 1 only 20. Identify the point on the graph of the function f (x) = x3 6x7 + 9x where the local minimum occurs. [A] (1, 4) [B] (0,0) [C] (1, -1) [D] (3,0) [E] (-1, -16)