Expression 4: "y" equals sine left parenthesis, StartFraction, 2 pi "x" Over 33 , EndFraction , right parenthesisy=sin2πx33
4
Biorhythm theory claims that humans are influenced by three fundamental cycles: a physical cycle of 23 days, an emotional cycle of 28 days, and an intellectual cycle of 33 days. The cycles are sine waves that begin at 0 on the day that you are born.
5
It should be noted that there is absolutely no scientific evidence for biorhythm theory, and it is almost certainly nonsense, but it is interesting from a mathematical perspective.
6
We might suppose that a person's well-being is determined by the sum of the three cycles. This function appears quite irregular, but in fact it has a period of 21,252 days. The graph is shown to the right.