4) The Population of the United Kingdom in July 2002 was estimated to be 59.8 million. At that time it was estimated that the population is growing according to the differential equation: dP = .0021P, where t is the number of years after July 2002. dt a) Find the function that satisfies initial-value problem. (5) b) Estimate the population of the United Kingdom in 2015 (after July). (2) c) After what period of time will population double that in 2002 ? (5)