A drug is administered every 4 hours in dose of 10 mg. The drug is neutralized at an exponential rate with decay rate constant k = 0.1. Not all the drug is neutralized before the next dose is administered. Let . A(t): denote the amount of drug in the patient's system at time t hours, . B : denote the amount of drug in the patient at the beginning of the n+1 dosage interval, and . R : denote the residual amount of the drug left in the patent at the end of the nth dosage interval. Note: The general form of the Exponential decay Model is A(t) = Aoe kt where: . Ao: denote the initial amount presented at time t = 0. . k: denote the decay rate (unit: 1/time) . A(t): denote the amount left at time t The formula for the function A(t) over the second dose periods is