Chapter 4.5, Problem 85E

(a)

To determine

To calculate: The sales in the first quarter, where $0\le t\le 3$ and sales is given by $S=74.50+\left(43.75\right)\cdot \sin \frac{\pi t}{6}$

(b)

To determine

To calculate: The sales in the second quarter, where $3\le t\le 6$ and sales is given by $S=74.50+\left(43.75\right)\cdot \sin \frac{\pi t}{6}$

(c)

To determine

To calculate: The sales in the year, where $0\le t\le 12$ and sales is given by $S=74.50+\left(43.75\right)\cdot \sin \frac{\pi t}{6}$