A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

anonymous

  • 4 years ago

Challenge: \[f(x)=\sum_{n=1}^{infinty}\sin(\frac{2x}{3^n})\sin(\frac{x}{3^n})\] find f(x) (independent of x) also evaluate the sum of the solutions of the equations f(x)=0 lying in the interval (0,629).

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

    I didn't make this up I have hundreds of such problems

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

    What book do you have for these?

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

    It is more of uncomplied collection

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

    Any ideas

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

    sin2x = 2cosx*sinx But it doesn't seem to work

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

    We shall use transformation formula

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

    cosc + cosd?

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

    sinxsin2x=1/2 (cosx-cos3x)

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

    Oh yeah cosc-cosd, Sorry

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

    You got it!

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

    NotSObright you're so bright! I think we have it now

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

    I know summation formula for cos of angles in AP not GP

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

    \[f(x) = \cos \frac{x}{3^n} - \cos x, n \to \infty \implies \frac{x}{3^n} \to 0 \implies \cos0 \to 1 \] \[f(x) = 1-\cos{x}\]

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

    I would like to answer more of such problems

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

    Thanka man

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

    f(x)=(1−cosx)/2

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

    yeah cant forget that 2

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

    Look at the new thread

  19. 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.