Outlays for national defense D (in billions of dollars) for 2006 through 2014 are shown in the table, where t is the time in years, with t = 6 corresponding to 2006.

(a) Use the regression capabilities of a graphing utility to find a model of the form D = at⁴ + bt³ + ct² + dt + e for the data.

(b) Use a graphing utility to plot the data and graph the model.

(c) For the years shown in the table, when does the model indicate that the outlay for national defense was at a maximum? When was it at a minimum?

(d) For the years shown in the table, when does the model indicate that the outlay for national defense was increasing at the greatest rate?

Transcribed Image Text:

t D t D 6 521.8 7 551.3 11 705.6 112 677.9 8 616.1 661.0 13 9 633.4 14 603.5 10 693.5