Quantcast

Got Homework?

Connect with other students for help. It's a free community.

  • across
    MIT Grad Student
    Online now
  • laura*
    Helped 1,000 students
    Online now
  • Hero
    College Math Guru
    Online now

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

mathslover Group Title

Find the value of : sin 47 (degrees) + sin 61 (degrees) - sin 11 (degrees) - sin 25 (degrees)

  • one year ago
  • one year ago

  • This Question is Closed
  1. 1on1 Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    set the calculator to degrees and start pressing buttons

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

    lol @1on1 , that's a shortcut but I do want to do that without *calculator*

    • one year ago
  3. 1on1 Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    Sorry, that will require much more thought from me !

    • one year ago
  4. mathslover Group Title
    Best Response
    You've already chosen the best response.
    Medals 2

    No problem! @sasogeek any suggestions, if no then I have only 1 .

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

    Not suggestion but an idea infact.

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

    use the calculator to find their actual values and do normal addition... that's if u want to do some work... if not, u may use the calculator to find the whole answer.

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

    hmn quite hard if calculator is not allowed.

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

    earlier i thought it was sin(A+B)-sin(A-B) sort of question but it's not, direct solution with the calculator is the way forward :) unless u know those values off the top of ur head xD

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

    xD thanks though

    • one year ago
  10. sasogeek Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    i do not wish to confuse you, but you may want to read this, http://www.trans4mind.com/personal_development/mathematics/trigonometry/sumProductCosSin.htm#Sum_of_Sine_and_Cosine

    • one year ago
  11. Yahoo! Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    @mathslover Do u knw the Value of Sin18 and cos36

    • one year ago
  12. Yahoo! Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    SinA + SinB = 2Sin (A+B)/2 . Cos (A-B)/2...Use this

    • one year ago
  13. mathslover Group Title
    Best Response
    You've already chosen the best response.
    Medals 2

    @Yahoo! and @sasogeek this was my main idea.

    • one year ago
  14. mathslover Group Title
    Best Response
    You've already chosen the best response.
    Medals 2

    Let me try again to find out the answer through the formula of sina + sinb

    • one year ago
  15. mathslover Group Title
    Best Response
    You've already chosen the best response.
    Medals 2

    OK so if I remember the values of : cos 36 degrees and sin 18 degrees then I am getting cos 7 degrees.

    • one year ago
  16. mathslover Group Title
    Best Response
    You've already chosen the best response.
    Medals 2

    cos Here is it how I did that : \[\large{\sin 47 + \sin 61 = 2 \sin 54 \cos 7 }\] ^that theta(s) are in degrees. similarly : \[\large{-(\sin 11 + \sin 25) = -( 2\sin 18 \cos 7)}\] from the above we get : \(2\cos 7 ( \sin 54 - \sin 18 )\) \(2\cos 7 ( 2\cos 36 \sin 18)\) \(4\cos 7 (\frac{\sqrt{5}+1}{4} \times \frac{\sqrt{5}-1}{4})\) \(\cos 7\) That is it! Is it correct? @sasogeek @Yahoo!

    • one year ago
  17. Yahoo! Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    Yup...thats wat i also Got

    • one year ago
  18. Yahoo! Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    2Sin54.cos7 - 2sin18cos7 2cos7 ( sin54 - sin18) sin54 = cos 36 2cos7(cos36 - sin18) 2cos7( (sqrt5 + 1)/2 - (sqrt5-1)/2) = cos7

    • one year ago
  19. Yahoo! Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    Sorry 2cos7( (sqrt5 + 1)/4 - (sqrt5-1)/4)

    • one year ago
  20. mathslover Group Title
    Best Response
    You've already chosen the best response.
    Medals 2

    np, thanks a lot for your help yahoo.

    • one year ago
  21. Yahoo! Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    Welcome....)...

    • one year ago
  22. Yahoo! Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    To..Be honest..U Did All the Hard Work..)

    • one year ago
    • Attachments:

See more questions >>>

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.