Solve the following:
Q: Let B(r,t) compute the balance (in dollars) of account after t years with an r% interest rate.
a) What are the units of dB/dr? (dB/dr is in partials notation)
b) Give a real world interpretation of dB/dr evaluated at (5,10) = 56.
c) If B(5,10) = 5000 and dB/dt evaluated at (5,10) = 165, estimate B(4,11). (dB/dt is partials notation)