A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

anonymous

  • one year ago

If sin theta=3/5 and theta is in quad 2 the exact form of cos (2theta) is I just need my work to be checked! because I got postive or neg sqrt -1/2

  • This Question is Closed
  1. welshfella
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 3

    cos (2theta0 = 1 - 2sin^2 theta

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

    Yeah I got that far knowing which formula to use

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

    so 1-2*(3/5)^2

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

    = 1 - 2*9/25

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

    Wait how tho?

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

    Thats not what I got at all lol

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

    7/25

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

    yes

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

    But how? It doesnt make sense lol @welshfella

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

    I'm assuming you mean 'cos 2 theta' not 'cos theta squared'?

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

    Yes exactly. Is it that simple then? Haha I was solving for sin @welshfella

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

    I do mean cos2theta

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

    yes - you just substitute 3/5 for sin theta

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

    Ohhhh I see @welshfella

  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.