Chapter 4.2, Problem 83PE

Application Exercises

In Exercises 43-44, use a calculator in radian mode in parts (b) and (c).

In

People who believe in biorhythms claim that there are three cycles that rule our behavior—the physical, emotional, and mental. Each is a sine function of a certain period. The function for our emotional fluctuations is

$E=\sin \frac{\pi }{14}t$

where t is measured in days starting at birth. Emotional fluctuations, E, are measured from -1 to 1, inclusive, with 1 representing peak emotional well-being, -1 representing the low for emotional well-being, and 0 representing feeling neither emotionally high nor low.

Find E corresponding to $t=7,14,21,28$, and 35. Describe what you observe

What is the period of the emotional cycle?