Quantcast

A community for students. Sign up today!

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

dquinao

  • one year ago

which is not a point on the circle x^2+(y-5)^2 =25? a.(0,5) b. (5,5) c. (5,0) d.(3,9)

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

    plug in those points and see which one holds true

  2. whpalmer4
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 2

    \(x^2+y^2 = r^2\) is the equation of a circle with radius \(r\) centered at the origin. In this case, \(r^2=25\) so the radius of the circle is \(5\) because \(5^2 = 25\). When we subtract or add something to \(x\) or \( y\) before squaring it, it has the effect of shifting the circle by the amount added or subtracted along the axis corresponding to the variable where we added or subtracted. Subtracting 5 from \(y\) has the effect of shifting the circle up by 5.

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

    resposta = d.(3,9) and so replace the x and y

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

    @ByteMe is the answer c?

  5. whpalmer4
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 2

    Come on, this is easy if you sketch the circle. |dw:1361068806890:dw| Now shift everything up by 5 (add 5 to the y value). Which point doesn't belong?

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

    yes... (5, 0) is NOT in the circle: \(\large x^2+(y-5)^2 =25 \) you are correct.

  7. whpalmer4
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 2

    |dw:1361068902180:dw|

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

    @whpalmer4 is the answer is d?

  9. whpalmer4
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 2

    No, the answer is that (5,0) is a point not on the circle, as you can see from the diagram.

  10. whpalmer4
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 2

    (3,9) you would have to check by substituting it in the equation, but given that the format of the question tells you that only one of the points isn't on the circle, it's clear that (5,0) is the only one.

  11. whpalmer4
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 2

    In general, it's useful to understand how adding and subtracting inside the squared terms moves the figure around. Much easier to recognize the effect than to figure it out by laboriously plotting values! :-)

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

    • Attachments:

Ask your own question

Ask a Question
Find more explanations on OpenStudy

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.