Chapter 8.3, Problem 25QY

(a)

To determine

To graph: Use a graph utility to graph the sale function if the company produces snowboard forecasts monthly sales for 1 year to be $S=53.5+40.5\cos \frac{\pi }{6}t$.

(b)

To determine

The months of maximum and minimum sales by using graph if the company produces snowboard forecasts monthly sales for 1 year to be $S=53.5+40.5\cos \frac{\pi }{6}t$.

(c)

To determine

The sales below $20 thousand during which year by using the graph if the company produces snowboard forecasts monthly sales for 1 year to be $S=53.5+40.5\cos \frac{\pi }{6}t$.