## anonymous 5 years ago any help on #3?? attachment?

1. anonymous

Attachment?

2. anonymous

?

3. anonymous

4. anonymous

Ohhh haha it wasnt showing on my screen sorry

5. anonymous

its hard as heak?

6. amistre64

$-1000 +\frac{1500x}{\sqrt{400+x^2}}=0$

7. anonymous

no #3

8. amistre64

whicih #3 then lol

9. anonymous

the long paragraph

10. amistre64

ooooo.... this one again

11. amistre64

ideally when the beach pipe cost equals the sea pipe cost you reach a balance point

12. amistre64

b(1000) + s(1500) = Equilibrium we just have to get a formula to equate b and to plug in

13. amistre64

s = sqrt(20^2 + (b-x)^2) where b-x is the distance between the rig and the shore pipe

14. amistre64

thats about the best i can do for equating the s and b

15. amistre64

b(1000) + sqrt(20^2 + (b-x)^2)(1500) = E solve for b right?

16. anonymous

yes x is the distance from the oil rigs vertical line to the shoreline..

17. anonymous

well it says my answer will be in terms of x?...

18. amistre64

maybe better like this tho: when b(1000) = s(1500) b(1000) = sqrt(20^2 + (b-x)^2)(1500) b(1000)/1500 = sqrt(20^2 + (b-x)^2) 2b/3 = sqrt(20^2 + (b-x)^2) ; ^2 both sides

19. amistre64

4b^2 ---- = 400 + (b-x)^2 9 4b^2 ----- = 400 + b^2 -2bx +x^2 9 4b^2 = 9(400 + b^2 -2bx +x^2) 4b^2 = 3600 + 9b^2 -18bx +9x^2

20. amistre64

4b^2 = 3600 + 9b^2 -18bx +9x^2 0 = (5)b^2 -(18x)b + (9x^2 + 3600) perhaps?

21. amistre64

to solve for b we can use the quadratic formula and insert all this other stuff as parameters

22. amistre64

18x sqrt(324x^2 - 4(5)(9x^2 + 3600)) --- + ----------------------------- and simplify lol 10 10

23. amistre64

sqrt(144x^2 - 72000) looks possible :)

24. anonymous

holy bageezus ... i uderstand the transitions and all ..and everything your doing ..but what are parameters?

25. amistre64

parameters are just the values we plug into the quadratic formula to make this easier; they relate to the coeffs of the b values

26. anonymous

oh okay!.

27. anonymous

so we cant reduce the last step by 12 or anything?

28. amistre64

sqrt(144x^2 - 72000) the innards here factor to what: sqrt(144(x^2 - 500)) 12 sqrt(x^2 - 500) if i did that part right lol

29. amistre64

our options for b are then: 9x 6sqrt(x^2 - 500) -- +- -------------- right? 5 5

30. anonymous

would the 500 then be 100?

31. amistre64

the 500 cant reduce the way i have it

32. amistre64

$\frac{9x \pm 6 \sqrt{x^2 - 500}}{5}$

33. anonymous

okay so we just add the numerators over 5!...yay!!

34. amistre64

if this is b we should be able to add this to x and get 30 right?

35. anonymous

OMGEE YES!!!!!

36. anonymous

you are amazing!!!!

37. anonymous

are you a professor or something?/

38. amistre64

just a something....

39. anonymous

haha mysterious i understand you a secret agent for the mathematical race of under delinquents?!?!?

40. anonymous

haha jk well thanks for the help!!

41. amistre64

:) libraries closing soon, so good luck with the rest; and I hope that helped out :)