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jfg4707
Average Member

USA
19 Posts

 Posted - 10/05/2007 :  14:15:33 Hi,I would like to know if I have answered the following questions correctly.ProblemA company sells S(t) thousand electric blankets in month t (with t=0 being January), where the approximate value of S(t) is given by S(t) = 72.25 + 41.5 sin(/6t + /2). Find the function's period and amplitude and explain their practical significance. Also, when does the period begin for this function? SolutionThe amplitude is |A| = 41.5. It's practical significance is that it represents the averge sales over the year.The period is given by P = 2/B = (2)/(/6) = 12. The period tells us the number of months for the sales to go through a complete cycle, i.e., 12 months.The function has a horizontal shift to the left given by C/B = (-/2)/(/6) = -3. Hence, the period begins in October.Thank you for any help you can give me.

tkhunny

USA
1001 Posts

 Posted - 10/05/2007 :  14:45:26 Everything but Amplitude. Try that again. I think 72.25 is the average sales. 41.5 dances around 72.25.

jfg4707
Average Member

USA
19 Posts

 Posted - 10/05/2007 :  15:27:53 Thank you, tkhunny.Yes, the midline (or line of oscillation) is the average sales for the year. The amplitude, 41.5, then, is amount of variation from that averge in a positive and a negative direction (or, the high and low variation from the average).
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