A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

anonymous

  • one year ago

PLEASE HELP!!!! Determine if the graph is symmetric about the x-axis, the y-axis, or the origin. r = 5 + 4 cos θ

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

    @ZeHanz please help

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

    Because of the 5 and 4, you can see that r takes values between 5-4=1 and 5+4=9. At theta=0 (and theta=2pi), r=9. At theta=pi (halfway the period), r=. What does this tell you about possible symmetries?

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

    its not even so it isnt around the x axis. right?

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

    so?

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

    @ZeHanz can you finish helping me please?

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

    Well, the graph cannot be symmetrical around the origin, because of this. Also, because (9,0) and (-1,0) are the points for theta=0 and theta=pi, the y-axis is not an axis of symmetry. So maybe the only symmetry left is the x-axis. Because the values of the cosine are the same before and after pi, this is indeed the case. This is what the graph roughly looks like:

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

    okay? so then how can you tell if it is around the x axis?

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

    Because the points above the x-axis belong to theta between 0 and pi, and the points below to theta between pi and 2pi. The cosine has the same values before and after pi, so the points lie symmetrical with respect to the x-axis. (Hope you understand what I want to say...)

  9. 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.