Consider the following function. x13 f(x) - In x 13 (a) Find the critical numbers of f. (Enter your answers as a comma-separated list.) x = 1 (b) Find the open intervals on which the function is increasing or decreasing. (Enter your answers using interval notation. If an answer does not exist, enter DNE.) increasing x>1 decreasing x <1 (c) Apply the First Derivative Test to identify all relative extrema. (If an answer does not exist, enter DNE.) relative maximum (x, y)=(0,0 relative minimum (x, y) = 1, 1 13