The total amount of money in circulation for the years 1990-2012 can be closely approximated by M(t) = 0.05023t3 1.124t2 + 38.69t + 247.9, where t represents the number of years since 1990 and M(t) is in billions of dollars. Find the derivative of M(t) and use it to nd the rate of change of money in circulation in the following years. a. 1990 b. 1995 c. 1998 d. 2001 e. What do your answers in parts a-d tell you about the amount of money in circulation in those years