calculus

The ozone level (in parts per billion) on a summer day in a certain metropolitan area is given by P(t) = 190 + 121 -21", where t is time in hours and t = 0 corresponds to 9 AM. (A) Use the four-step process to find P'(t). (B) Find P(2) and P'(2) (A) Use the four-step process to find P'(t) P' (1)= (B) Find P(2) and P' (2) P(2) = (Simplify your answer.) P'(2) = (Simplify your answer.)