1. (5 points) Let x22 if x3. Please answer the following two questions with justication. ' ' ? (a) Does 31:12}, f (x) ex1st. (b) If f continuous at x = 3? 2. (5 points) Let x - 4 f ( x ) = x2 - 16 Find out all horizontal and vertical asymptotes of f.3. (5 points) Suppose a tank originally has SOUL water which contains 50g salt. Brine that contains 3g of salt per liter is pumped into the tank at the rate of 10L / min. (a) What is the concentration C (t) of salt in the tank after t minutes? (b) Compute lEln C(t). 4. (5 points) Let 1 f (x) = 2x - 3' Compute f'(2) using the limit definition of the derivative. (Warning: no credits will be given if directly applying the derivative formula.)