45,000 Suppose that the demand function for a product is given by D(p) = and that the price p is a function of time given by p = 1.8t + 9, where t is in days. p a) Find the demand as a function of time t. b) Find the rate of change of the quantity demanded when t = 100 days. . . . a) D(t) = (Simplify your answer.) b) What is the approximate rate of change of the quantity demanded when t = 100 days? units day (Simplify your answer. Round to three decimal places as needed.)