Find the extreme values of the function x) 2 3 cos _1 (x6) and where they occur. The function f has absolute maximum value D at the critical point x = D and absolute minimum value D at the singular points x = D [Simplify your answer{s). Tvpe an exact answer(s}, using 1: as needed. Use a comma to separate answers as needed. Use integers or fractions for any numbers in the expression.)