A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

anonymous

  • one year ago

Find the standard form of the equation of the parabola with a focus at (-4, 0) and a directrix at x = 4.

  • This Question is Closed
  1. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    |dw:1440121717847:dw|

  2. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    HJI!!

  3. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    you need the vertex first, also which way it is oriented then it is quite quick do you know the vertex?

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

    0,0?

  5. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    yes !

  6. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    and how is it oriented? |dw:1440121829542:dw|

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

    first?

  8. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    yes again

  9. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    |dw:1440121936412:dw|

  10. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    because it opens to the left, that means the \(y\) term is squared, and it will look like \[y^2=px\]

  11. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    all you need is \(p\) the distance from the vertex to the focus, or from the directrix to the vertex what is that distance?

  12. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    oops i made a typo \[y^2=4px\] is what i meant

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

    p=4

  14. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    ok so final answer \[y^2=-16x\]

  15. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    minus because it opens to the left

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

    oh okay so you just have to look for each part and then put it together THANK YOU SO MUCH!!

  17. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    right want to check the answer?

  18. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    \[\color\magenta\heartsuit\] http://www.wolframalpha.com/input/?i=parabola+y%5E2%3D-16x

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

    y = negative one divided by sixteenx2

  20. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    oh no!

  21. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    the y term is squared, not the x term

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

    ohh yeah sorry haha

  23. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    if \[y^2=-16x\] is not an "answer choice" try \[x=-\frac{1}{16}y^2\]

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

    could we do another one like this and you help me the same way?

  25. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    kk

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

    Find the standard form of the equation of the parabola with a focus at (0, -9) and a directrix y = 9.

  27. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    |dw:1440122328669:dw|

  28. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    vertex?

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

    so it open down? vertex is 0,0

  30. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    yeah opens down so the x term is squared and its coefficient it negative

  31. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    distance is clear right?

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

    p=9

  33. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    right so \[x^2=-36y\] should do it

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

    wait how did 36 come from 9

  35. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    \[4\times 9\]

  36. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    \[x^2=4py\]

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

    ohhh yeah okay haah and wouldn't it be y=-1/36x2

  38. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    that too

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

    oh okay

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

    thank you so much! If I have any more tonight ill tag you in them :)

  41. misty1212
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    \[\huge\color\magenta\heartsuit\]

  42. 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.