5. Which of the following ensures that a function f is continuous at 3? (a) lim f(x) exists. (b) f(3) exists. (c) lim f(x) = f(3). 2-3 (d) All of the above. (e) None of the above. Answer: Problem 6. (1 point) Why is the following function discontinuous at 0? (a) f(0) does not exist. (b) lim f(x) does not exist (or is infinite). 20 (c) Both (a) and (b). (d) f(0) and lim f(x) exist, but they are not equal. 0 if a < 0 *-(E8 f(x) = ifr 20