A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

anonymous

  • one year ago

Derive the equation of the parabola with a focus at (0, −4) and a directrix of y = 4. f(x) = −16x2 f(x) = 16x2 f(x) = −one sixteenth x2 f(x) = one sixteenthx2

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

    @satellite73 @princeharryyy

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

    @pooja195

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

    Ans: f(x) = (-1/16)*(x²) D.

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

    how did you get that ?

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

    @WhateverYouSay

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

    If the focus is at (0,-4) and the directrix is y = 4 then the vertex of the parabola is midway between these two features at (0,0). The parabola is thus a downward opening parabola with the standard equation x² = 4cy where c is the distance from the vertex to the focus. In this question, c = -4.

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

    is that the formula that you would use for all parabola equations?

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

    @nono266 can you explain this better?

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

    @ganeshie8

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

    well it say's it's the standard equation. So i am assuming yes...

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

    how do you know which one is 'C'

  12. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    still need help!

  13. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    ??? @scenemunster

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

    yes please

  15. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    ok! from the start.

  16. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    should we?

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

    yes how do you do that?

  18. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    The parabola can look like

  19. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    |dw:1438718841051:dw|

  20. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    can u see that. @scenemunster

  21. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    and please if u are interested in learning u must be interactive. or u can just have answers. @scenemunster It's up to you.

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

    yes

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

    i understand

  24. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    let's take a general form. suppose this figure.

  25. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    |dw:1438719011601:dw|

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

    this amkes no sense to me tbh

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

    makes

  28. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    now, In this figure Point B is known as the vertex of the parabola, A is known as the focus, and line D is known as Directrix of the parabola.

  29. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    where C is at the same distance from origin as is the focus of parabola.

  30. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    has, it started making sense @scenemunster

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

    yes

  32. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    great, The general equation of east facing parabola, whose vertex is at (0,0) is y^2 = 4ax

  33. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    are you getting it.

  34. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    where a is the distance from vertex to the focus of the parabola

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

    so (a,o)?

  36. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    as distance being a, and the for every positive x there will be two values of y one negative and the other positive , the parabola is sketched this way. i.e., east facing.

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

    im so confused

  38. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    where

  39. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    ?

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

    the east facing parabola

  41. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    |dw:1438719685600:dw|

  42. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    TAKING THIS AS CONVENTION, ARE U COMFORTABLE NOW.

  43. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    @scenemunster ??? please be quick! I don't have much time.

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

    ok so a =4?

  45. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    4 comes in general equation. they made the general equation this way

  46. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    a is some constant which changes it's value according to question.

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

    @amistre64 can you help as well. im sorry im naturally blonde and i dont know XD

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

    so what is the equation like how do i set it up

  49. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Ok, leave that.

  50. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    for your question.

  51. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    let me make the figure.

  52. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    |dw:1438720085660:dw|

  53. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    where a =-4. y = -16x^2

  54. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    focus of parabola (0,-4)

  55. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    That means the answer is a

  56. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    @scenemunster

  57. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    ok. i understand but y would it be a my guess was d

  58. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    wait a second, it won't actually be A or D it would be C, reason, general equation, x^2 = -4by => x^2 = -16y, b=4 =>y =-x^2/16

  59. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    ok. my besty said the same thing

  60. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    @scenemunster , n sorry actually I was explaining the east one so by mistake I told u A earlier.

  61. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    and, later we changed the direction of parabola to south and hence the equation changed. Sorry 'bout that but the answer is C for 100%

  62. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    @scenemunster

  63. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    ok i got it thank you

  64. princeharryyy
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    yw :)

  65. 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.