For the Next 15 Years, a Small Company's Business Volume $f(x)=47(1.09)^{x}+3 \sin \frac{\pi x}{6}$

Essay

For the next 15 years, a small company's business volume can be modeled by the function
$f(x)=47(1.09)^{x}+3 \sin \frac{\pi x}{6}$ where x is the number of years after 2006 and f is the sales in millions of dollars.
(a) What are the company's sales in 2006?
(b) What does the model project for sales in 2013?
(c) How many years are in each economic cycle for this company?