Part | Models with differential equations (3 and 4, 3 points, 1.5 each) Experiments have shown that the rate at which a radioactive element decays is directly proportional to the amount of it present (3 and 4). 'l.Write the differential equation that represents the situation (assume that the quantity of the element when time is t is y = N(t). 2.Solve the above differential equation given that n(0) = n0