A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

anonymous

  • 5 years ago

Can someone help me finish this problem I took it as far as I could... If x=9sinθ, use trigonometric substitution to write √(81-x^2) as a trigonometric function of θ, where -pi/2<θ<pi/2.

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

    So far I have √(81-9sinθ^2) 81√(1-sinθ^2) 1-sin^2θ=1/cscθ ?

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

    or maybe It is 9√(1-sinθ^2)...

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

    yes

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

    your second post was right

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

    √(81-81sinθ^2) <--- (9sinθ)^2 = 81sinθ^2 = 9√(1-sinθ^2)

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

    next you need to figure out which trig substitution to use

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

    Thank you! would the answer be 9cscθ then?

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

    \[\sin ^{2}\theta+\cos ^{2}\theta = 1\] is a where you want to start thinking about your substitution

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

    the answer isn't 9cscθ, but you are almost there

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

    use \[1-\sin ^{2}\theta = \cos ^{2}\theta\]

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

    oh ok...where did the cos come from? I thought sinθ=1/cscθ so in this case it would be 1-sin^2θ=1/cscθ ?

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

    ok so 9cosθ?

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

    yes :)

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

    Sweet! thanks a bunch!

  15. 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.