During the human female menstrual cycle, the gonadotropin, FSH or follicle stimulating hormone, is released from the pituitary in a sinusoidal manner with a period of approximately 28 days. Guyton's text on Medical Physiology shows that if we define day 0 (t=0) as the beginning of menstration, then FSH, F(t), cycles with a high concentration of about 3.8 ("relative units") around day 9 and a low concentration of about 1.5 around day 23.
a. Consider a model of the concentration FSH (in "relative units'') given by
F(t) = A + B cos (ω (t-Φ))
where A, B, ω, and Φ (with 0 ≤ Φ ≤ 28 ) are constants and t is in days. Use the data above to find the four parameters.
If ovulation occurs around day 14, then what is the approximate concentration of FSH at that time?