Ay 4000- 3500 3000 G 2500 2000 1500 1000 500 0- 0 2 4 6 8 10 12 Years after 1980 14 The blue curve shows national health expenditures in billions of dollars. The red curve shows its derivative National health expenditures (in billions of dollars from 1980 to 1992 are given by the function f(t) in the graph to the left. (a) How much money was being spent at the beginning of 1981? $ 700 billion (b) Approximately how fast was the rate of spending increasing in 1988? $ billion per year