Quantcast

A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

sierraurb

  • one year ago

PLEASE HELP!! A rain gutter is to be constructed of aluminum sheets 12 inches wide. After marking off a length of 4 inches from each edge, this length is bent up at an angle Θ. The area A of the opening may be expressed as the function: A(Θ) = 16 sin Θ • (cos Θ + 1). If Θ = 90°, what is the area of the opening? When i plug 90 in i keep getting 15, but my choices are: 21.8 in2 16.0 in2 7.9 in2 1.0 in2

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

    @dangerousjesse any luck?

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

    @phi @vineeth10

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

    @ganeshie8 @MATHMALE

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

    first, you can do this without a calculator. But if you do use a calculator, be sure it is in degree mode. you should(!) know sin(90º)= 1 and cos(90º)= 0

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

    @phi i just figured it out actually!! C right? and could you please help me with one more!! im stuck on it :/

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

    Simplify \[\sqrt{\left( 1-\sin \Theta \right)\left( 1+\sin \Theta \right)}\]

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

    @phi i have no idea what to do

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

    First, How did you get C 7.9? It seems if sin(90) is 1 and cos(90) is 0 you would do 16 sin Θ • (cos Θ + 1) 16 • 1 •(0+1) and now we add 0+1 (not *too* hard) and multiply that by 16*1 you don't get 7.9

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

    For some reason i divided 16 in 2 idk why haha thank you!!

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

    any idea what the answer is for your first question?

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

    b right?

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

    any idea on how to solve the second one? i really have no idea what to do @phi

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

    do you know how to multiply the two binomials inside the square root (some people use FOIL)

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

    if you don't see http://www.khanacademy.org/math/algebra/multiplying-factoring-expression/multiplying-binomials/v/multiplying-binomials

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

    yeah when i foil i get sqrt(1-sin O)

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

    is that right? @phi

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

    can you show your work?

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

    F: 1*1=1 O: 1*sinO=sinO I: -sinO*1=-sinO L: -sinO*sinO=-sin2 so its sqrt(1-sin^2) oops!

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

    these are my options btw @phi ±sin Θ |cos Θ| ±tan Θ square root sine theta

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

    ok looks better there is a *very useful* identity you should remember for trig problems \[ \sin^2 x + \cos^2 x = 1 \] which you can rewrite as \[ \sin^2 x = 1 - \cos^2 x \] or \[ \cos^2 x= 1 - \sin^2 x \]

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

    would it be B?

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

    yes. replace 1 -sin^2 with cos^2 inside the square root sqrt(cos^2) = cos is the only choice that looks close (they must only want the positive root) | cos Θ |

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

    @phi thank you so so much!! i really truly appreciate it :)

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

    yw

  25. 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.