Dialysis treatment removes urea and other waste products from patients' blood by diverting some of their bloodflow externally through a machine called a dialyzer. The rate at which urea is removed from the blood (in mg/min) is often well described by the equation u(t) = r V C0e−rt/V where r is the rate of flow of blood through the dialyzer (in mL/min), V is the volume of the patient's blood (in mL), and C0 is the amount of urea in the blood (in mg) at time t = 0. Evaluate the integra ∫0 a 45 u(t) dt