Answer:
f(x) = 10500sin(π/6(x -3)) +39500
Explanation:
The average of the maximum and minimum revenue is the vertical offset of the function, parameter D.
D = (50,000 +29,000)/2 = 39,500
The amplitude of the function is the difference between the maximum and the offset.
A = 50,000 -D = 50,000 -39,500 = 10,500
The horizontal scale factor B is a number that will be equal to 2π when x-C = 12:
12B = 2π
B = π/6 . . . . . . divide by 12
The horizontal offset is such that revenue is neutral and increasing at the value x=C. That will be in the month of March, when x=3, so C=3.
Now we have all the parameters, so we can write the equation:
f(x) = 10500sin(π/6(x -3)) +39500