britbrat4290 2 years ago PLZ HLP!:) The weekly sales in thousands of items of a product has a seasonal sales record approximated by (t is time in weeks with t = 1 referring to the first week in the year). During which week(s) will the sales equal 96,990 items?

1. britbrat4290

2. Coolsector

ok so what did you try to do ?

3. britbrat4290

im ost in this cant u cant lol im forced to take a high school calc class and this isnt even calc fml i just cant fail this last test

4. britbrat4290

lost

5. britbrat4290

i know how to plug in formulas thats about it to be honest

6. Coolsector

im sorry to hear that :( anyway you have this equation that you gave me it describes the amount of itmes for a given t (week)

7. Coolsector

you look for a certain amount of items and find the corresponding t

8. britbrat4290

ok

9. britbrat4290

plug in one for t for everything

10. Coolsector

no, you want to find t

11. britbrat4290

12. Coolsector

im 23 as well .. it is fine

13. britbrat4290

but i thought it says t=1 in the problem

14. britbrat4290

:)

15. Coolsector

no, they say that t=1 means the first week

16. britbrat4290

ahh gotcha

17. Coolsector

now when you find t , for example if you find t = 10 you know that it is the 10th week in year

18. Coolsector

now, you got the equation : n=84.59 + 24.8sin(pi*t/24)

19. Coolsector

and they ask you for what weeks n = 96,990

20. britbrat4290

i got undefined ...

21. Coolsector

so you have to solve: 96,990 = 84.59 + 24.8sin(pi*t/24) i guess here 84.59 means 84590 and 24.8 means 24800

22. Coolsector

so it is really should be : 96.99 = 84.59 + 24.8sin(pi*t/24)

23. Coolsector

since they say "n is in thousands of items"

24. britbrat4290

im getting a crazy calculation

25. britbrat4290
26. Coolsector

why, look: 96.99 = 84.59 + 24.8sin(pi*t/24) 12.4 = 24.8sin(pi*t/24) 0.5 = sin(pi*t/24)

27. britbrat4290

week 4, week 20, and week 52?

28. Coolsector

wait ill check :)

29. Coolsector

0.5 = sin(pi/6) so : sin(pi/6) = sin(pi*t/24) 1. pi*t/24 = pi/6 + 2pi*k t = 4 + 48*k t = 4 , 52 2. pi*t/24 = pi - pi/6 + 2pi*k t = 20 + 48*k t=20 so yes! 4 20 52

30. britbrat4290

yay ur being my life saver right now!!!

31. britbrat4290

THANK U SOO MUCH

32. Coolsector

yw :))