Determine whether each statement is true or false and explain why. (1) For a continuous function on a closed interval, one can determine the absolute extrema by evaluating the function at the end points and at each critical number. (2) If a function on a closed interval has only one critical number at =, then by the critical point theorem, the function has an absolute extremum at =.(3) For a function on an open interval, absolute extrema will occur at every critical number. (4) A function on an open interval cannot have both an absolute maximum and an absolute minimum.