A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

anonymous

  • 3 years ago

Help with related rate problem please! (DISTANCE)

  • This Question is Closed
  1. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

  2. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    hint -> you want dy/dt so: dy/dt = (dy/dx) * (dx/dt)

  3. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    which formula do i use?

  4. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    you have dx/dt at this point and you have the point itself. that should help you

  5. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    right.

  6. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    got that.

  7. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    dy/dt = (dy/dx) * (dx/dt)

  8. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    dy/dx means derivative of y with respect to x dx/dt is given at this point

  9. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    i know.

  10. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    so?

  11. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    but what formula should i use, for example there are problems for volume, circle, triangle, etc.

  12. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    distance formula?

  13. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    ok so distance from the origin is s = sqrt(x^2 + y^2) so you want ds/dt = (ds/dy) * (dy/dt) + (ds/dx) * (dx/dt)

  14. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    what does s symbolize?

  15. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    right.

  16. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    s - distance

  17. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    so that is it. now you have it all

  18. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    thanks let me try

  19. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    you can, as well, to express y in terms of x in the distance formula and then find ds/dt = (ds/dx) * (dx/dt) it will be much more simple

  20. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    right the whole 5*sqrt(2x+2) is throwing me off though,

  21. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    im not sure if i should find the derivative of that function with respect to time.

  22. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    and the whole distance formula too.

  23. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    ok so if we do it the way i said at the end : "you can, as well, to express y in terms of x in the distance formula and then find ds/dt = (ds/dx) * (dx/dt) it will be much more simple" then you dont have to do much

  24. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    cause s=sqrt(x^2 + y^2) = sqrt(x^2+50x+50) now ds/dt = (ds/dx) * (dx/dt)

  25. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    you just need to find ds/dx

  26. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    i did this: i found s=10.0499 then i found the derivative which i got 5/sqrt(2x+2) *dx/dt

  27. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    i got ds/dt as 10 but i know it's wrong.

  28. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    you dont need to find s. you need to find ds/dx

  29. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    ds/dx=10

  30. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    what about dy?

  31. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    since we express y in terms of x we dont need to worry about it anymore.

  32. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    ok

  33. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    ds/dx = (x + 25)/sqrt(x^2+50x+50) at the point x=1 it is ds/dx = 26 / sqrt(101) so ds/dt = (26 / sqrt(101))* 4 i might done some mistake though

  34. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    yeah im not sure what's happening.

  35. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    why? s = sqrt(x^2+y^2) = sqrt(x^2+50x+50) so we want ds/dt ds/dt = ds/dx * dx/dt ds/dx = (x + 25)/sqrt(x^2+50x+50) ds/dx at this point = 26/sqrt(101) so ds/dt at this point = 26 * 4 /sqrt(101)

  36. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    plugged into the derivative x=1 and dx/dt = 4

  37. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    understand what i did ?

  38. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    sqrt(x^2+50x+50) ?

  39. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    this is the distance.. s=sqrt(x^2 + y^2) = sqrt(x^2 + 50x + 50)

  40. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    i know, how'd you come up with this sqrt(x^2+50x+50)

  41. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    x^2+50x+50)

  42. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    plugged y=5sqrt(2x+2)

  43. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    10=10

  44. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    50x+50?

  45. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    i plugged in y and x

  46. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    what ?

  47. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    y=5sqrt(2x+2) y^2 = 50x+50

  48. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    plugged y=5sqrt(2x+2). i plugged in y and x. 10=10

  49. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    so now s = sqrt(x^2 + y^2) but since y^2 = 50x+50 s = sqrt(x^2+50x+50)

  50. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    not the value of y at the point. plug y as a function of x

  51. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    okay thanks alot.

  52. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    i got it

  53. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    are you sure ?

  54. anonymous
    • 3 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    s = sqrt(x^2+y^2) = sqrt(x^2+50x+50) so we want ds/dt ds/dt = ds/dx * dx/dt when we calculate ds/dx we calculate is using s as a function of x. not plugging numerical values yet. ds/dx = (x + 25)/sqrt(x^2+50x+50) now plug x=1 ds/dx at this point = 26/sqrt(101) so ds/dt at this point = 26 * 4 /sqrt(101)

  55. Not the answer you are looking for?
    Search for more explanations.

    • Attachments:

Ask your own question

Sign Up
Find more explanations on OpenStudy
Privacy Policy

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.