SOLUTION: Mr. Wong has noticed a whole lot of sneezing in his class in a past few years. He has investigated the situation and has gathered some information. • The highest percent of the

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Question 1181064: Mr. Wong has noticed a whole lot of sneezing in his class in a past few years. He has investigated the situation and has gathered some information.
• The highest percent of the population suffering from allergies is 20% and it happens in May
• The lowest percent of the population suffering from allergies is 10% and it happens in November
• The pattern repeats yearly (every 12 months)
Let P be the percent of the population suffering from allergies and t be time in months after January (i.e.January is when t = 0), determine an equation that models this situation. (this is about sinusoidal functions)

Answer by ikleyn(52890) About Me  (Show Source):
You can put this solution on YOUR website!
.

I will use the cosine function.


The middle level is P = 0.15, and the amplitude is 0.05, obviously.


So, I write  P(t) = 0.15 + 0.05*cos(2pi*x).


The starting value for the factor  "x"  is 0  at  t= 5  ( x  must be 0 at May ), and the period is  12  months (one year).


So, I take  x = %28t-5%29%2F12,  and then my final formula is


    P(t) = 0.15+%2B+0.05%2Acos%282pi%2A%28%28t-5%29%2F12%29%29,      ANSWER


where t is the index showing the month of the year.  For clarity,  t = 5 for May.

Solved, answered and carefully explained.