Question

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A person who was listening to a siren reported that the frequency of
the sound fluctuated with time, measured in seconds. The minimum
frequency that the person heard was 500 Hz, and the maximum
frequency was 1000 Hz. The maximum frequency occurred at t=0 and t=15. 
The person also reported that, in 15, she heard the maximum frequency 6 times(including the times at t = 0 and t = 15)
What is the equation of the cosine function that describes the frequency of this siren?

Answer 1

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Answer 2

Since the maximum frequency was heard 6 times between t= 0 and t= 15, and each maximum gives one cycle, there are 5 (not counting the first max which starts a cycle) cycles.

Answer 3

So the frequency is 5/15= 1/3 cycle per second.

Answer 4

Each cycle is 2pi radians so the frequency is 2pi/3 radians per second.

Answer 5

Wait how you get the 5

Answer 6

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