Quantcast

Got Homework?

Connect with other students for help. It's a free community.

  • across
    MIT Grad Student
    Online now
  • laura*
    Helped 1,000 students
    Online now
  • Hero
    College Math Guru
    Online now

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

QRAwarrior Group Title

How would you draw a cylinder for the shell method for the region that is enclosed by x = pi/2, x = -pi/2 and y = cosx? This is rotated about y = -1.

  • 2 years ago
  • 2 years ago

  • This Question is Closed
  1. QRAwarrior Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    @FoolForMath @myininaya @experimentX @shivam_bhalla @amistre64 @Zarkon @Hero Anyone?

    • 2 years ago
  2. QRAwarrior Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    @jim_thompson5910

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

    the definite integrand of f(x)=cosx from -pi/2 to pi/2 sinx from -pi/2 to pi/2 = 1-(-1)=2

    • 2 years ago
  4. QRAwarrior Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    I do not want the answer. @akamushi

    • 2 years ago
  5. QRAwarrior Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    @FoolForMath @myininaya @experimentX @shivam_bhalla @amistre64 @Zarkon @Hero Anyone?

    • 2 years ago
  6. QRAwarrior Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    @FoolForMath @myininaya @experimentX @shivam_bhalla @amistre64 @Zarkon @Hero Anyone?

    • 2 years ago
  7. lgbasallote Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    @lgbasallote lol jk...idk shell using trig functions

    • 2 years ago
  8. PROSS Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    |dw:1337557715702:dw|

    • 2 years ago
  9. QRAwarrior Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    The height would be 2cosx, and the radius would be cosx - (-1)?

    • 2 years ago
  10. QRAwarrior Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    ie. h = 2y r = y - (-1) ?

    • 2 years ago
  11. QRAwarrior Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    |dw:1337558085638:dw|

    • 2 years ago
  12. QRAwarrior Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    The height (which are the horizontal lines of the cylinder) would be given by h = 2cosx? And the radius would be given by r = cos(x) - (-1)?

    • 2 years ago
  13. QRAwarrior Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    Wait, I think the height would be: h = 2x, due to symmetry

    • 2 years ago
  14. QRAwarrior Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    |dw:1337558202025:dw|

    • 2 years ago
  15. QRAwarrior Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    So then, radius is r = cos(x) - (-1) for sure, right?

    • 2 years ago
  16. QRAwarrior Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    And I can restate that cos(x) as y So then, r = y +1, h = 2x = 2arccos(y), I believe.

    • 2 years ago
  17. PROSS Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    now you are on the right track.

    • 2 years ago
  18. PROSS Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    if you are familiar with winplot, you can make a nice 3d representation.

    • 2 years ago
  19. QRAwarrior Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    @shivam_bhalla! Yes you finally came.

    • 2 years ago
  20. QRAwarrior Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    |dw:1337558589994:dw|

    • 2 years ago
  21. QRAwarrior Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    I have one question for either of you: I drew a vertical line from the x-axis to the function cos(x). Can that generically be represented as y?

    • 2 years ago
  22. shivam_bhalla Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    @QRAwarrior , try this http://openstudy.com/updates/4fb44286e4b05565342a2a03 You will find it a lot more helpful :) The answer to your question you asked before is yes

    • 2 years ago
  23. amistre64 Group Title
    Best Response
    You've already chosen the best response.
    Medals 3

    x = pi/2, x = -pi/2 and y = cosx|dw:1337561871090:dw|

    • 2 years ago
  24. amistre64 Group Title
    Best Response
    You've already chosen the best response.
    Medals 3

    |dw:1337562804283:dw|

    • 2 years ago
  25. QRAwarrior Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    Ok so it is: h = x y = cosx - (-1)

    • 2 years ago
  26. amistre64 Group Title
    Best Response
    You've already chosen the best response.
    Medals 3

    we only need half of this, then double the results height is a measure of arccos(y) radius is from from 1 to 2 by perspective \[2*2pi\int_{0}^{1}(y+1)*\cos^{-1}(y)\ dy\]

    • 2 years ago
  27. QRAwarrior Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    I think I came up with this a few posts back

    • 2 years ago
  28. amistre64 Group Title
    Best Response
    You've already chosen the best response.
    Medals 3

    height is a function of x; y=cos(x) arccos(y) = x = height

    • 2 years ago
  29. QRAwarrior Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    -------------------------------------------------------- Ok consider this question: Find the length of y^2 = x^3 from (0,0) to (4,8) I know the formula for arclength, but I end up getting this: |dw:1337563218324:dw|

    • 2 years ago
  30. QRAwarrior Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    |dw:1337563244465:dw|

    • 2 years ago
  31. QRAwarrior Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    How the heck can you resolve the radical when you have: |dw:1337563293983:dw| As your argument?

    • 2 years ago
  32. amistre64 Group Title
    Best Response
    You've already chosen the best response.
    Medals 3

    have you tried looking at it form both forms? \[\sqrt{1+(x')^2}\ or\ \sqrt{1+(y')^2}\]

    • 2 years ago
  33. QRAwarrior Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    No. I think I will try the other form, BUT the problem is that I am not sure whether to pick the POSITIVE root or the NEGATIVE root..

    • 2 years ago
  34. amistre64 Group Title
    Best Response
    You've already chosen the best response.
    Medals 3

    for the most part, i think you stick with the positive root

    • 2 years ago
  35. QRAwarrior Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    Why do you say "most part"

    • 2 years ago
  36. amistre64 Group Title
    Best Response
    You've already chosen the best response.
    Medals 3

    distance tends to be a measure in absolute value, so the positive root seems most apt

    • 2 years ago
  37. QRAwarrior Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    WOW! I just realized how EASY it is doing it wrt x.

    • 2 years ago
  38. QRAwarrior Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    |dw:1337563549037:dw|

    • 2 years ago
  39. QRAwarrior Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    Easy U-sub. Thanks a lot amistre64. What level of education is your mathematics?

    • 2 years ago
  40. QRAwarrior Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    I was just curious

    • 2 years ago
  41. amistre64 Group Title
    Best Response
    You've already chosen the best response.
    Medals 3

    i dunno what level it is, im guessing its at least on a 3rd grade level ;)

    • 2 years ago
  42. QRAwarrior Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    Ok anyways, thanks for your help

    • 2 years ago
  43. amistre64 Group Title
    Best Response
    You've already chosen the best response.
    Medals 3

    youre welcome. Levelwise is difficult since im self taught for the most part of this stuff

    • 2 years ago
    • Attachments:

See more questions >>>

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.