For a single compartment model that initially contains no activity, derive the expressions and solve for the activity (q) and the disintegrations (U) in the compartment at t= 2 minutes given that the physical (radioactive) half-life is 2 minutes, the biological half-life is 2 minutes, and the input rate (R) is a linear function with a slope of 10 Bq minute-2 and an intercept of zero.