Answer:
A
Explanation:
To predict the sales for June 2010, we need to substitute the value of t corresponding to June 2010 into the given sales forecast equation. Since January 2010 is represented by t = 1, June 2010 would be represented by t = 6.
Plugging in t = 6 into the equation S = 23.1 + 0.4421 + 4.3 * cos(tπ/6), we get:
S = 23.1 + 0.4421 + 4.3 * cos(6π/6)
S = 23.5421 + 4.3 * cos(π)
Evaluating cos(π), we find that cos(π) = -1. Substituting this value into the equation:
S = 23.5421 + 4.3 * (-1)
S = 23.5421 - 4.3
S ≈ 19.242
Rounding the answer to three decimal places, we get S ≈ 19.242.
Therefore, the predicted sales for June 2010 (rounded to three decimal places) is approximately 19.242 thousand units.
The closest option is A. S ≈ 19.452 (19,452 units).