1. Suppose P(t) is the monthly payment, in dollars, on a mortgage which will take t years to pay off. What are the units of P'(t)? What is the practical meaning of P'(t)? What is its sign?
2. After investing $1000 at an annual interest rate of 7% compounded continuously for t years, your balance is $B, where B = f(t). What are the units of dB/dt? What is the financial interpretation of dB/dt?