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. A.f(x) = −16x2 B.f(x) = 16x2 C.f(x) = −one sixteenth x2 D.f(x) = one sixteenthx2

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

    @random231 @aaronq @sourwing @princeharryyy @satellite73 @DarkMoonZ @Baby_Bear69

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

    the general form is x^2 = 4ay where a = the y coordinate of the focus can you work it out ?

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

    what do i work out sorry i have no idea what to do with these types of questions

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

    the focus is at (0,-4) - that is the y coordinate is - 4

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

    x^2 = 4(-4)y

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

    this type of parabola as the origin at (0,0) because x = 0 when y = 0 and as the focus is negative 4 opens downwards

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

    so x^2=16y?

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

    |dw:1439568914238:dw|

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

    no x^2 = -16y divide both sides by -16 f(x) = y = - 1 x^2 ---- 16

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

    C is the correct choice

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

    so A ?

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

    oh C

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

    A is sixteen C is negative sixteenth

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

    so what would be the equation to solve it ?

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

    the equation of the curve is f(x) = - one sixteenth x^2

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

    yea but to solve Derive the equation of the parabola with a focus at (−5, −5) and a directrix of y = 7.

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

    |dw:1439569218616:dw|

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

    oh thats a new question

  19. 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.