Quantcast

A community for students. Sign up today!

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

Babybee24

  • one year ago

cos^2(x)+cos(x)sin(x)=0 solve for x

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

    Try factoring

  2. Babybee24
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    I factored a cos(x) out but then im stuck

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

    cos(x)( ? + ? ) =0 So what should be in the places of those ?'s once you factor out cos(x)?

  4. Babybee24
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    cos(x)(cosx+sinx)

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

    Yes. Set both factors equal to 0. cos(x)=0 ; cos(x)+sin(x)=0

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

    Solve cos(x)=0 for x And find the value x so that cos(x) and sin(x) are opposites (i.e cos(x)=-sin(x))

  7. Babybee24
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    cosx=pie/2 ?

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

    cos(x)=0 for x=pi/2 cos(x) does not equal pi/2 But one value that satisfies cos(x)=0 is x=pi/2 Are there any other values?

  9. Babybee24
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    x=3pi/2

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

    Ok and you can also say we have x=pi/2+2npi where n is an integer or x=3pi/2+2n pi where n is an integer

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

    We also need to find the values of x where cos(x) and sin(x) have opposite values.

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

    |dw:1357920385873:dw| As you can see they will be opposite in quadrant 2 and 4.

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

    |dw:1357920430907:dw| These points is where cos(x) and sin(x) are opposite. Now what angle are these points at from the initial ray?

  14. Babybee24
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    135 and 315?

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

    Correct.

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

    Now should your answer be in radians or degrees?

  17. Babybee24
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    um radians?

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

    So 135*pi/180 or 315*pi/180

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

    Don't forget we can go around the circle infinitely many times from those angles.

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

    So 135pi/180+2npi , 315pi/180+2npi

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

    Don't forget the other solutions we wrote above. Good job. :)

  22. Babybee24
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    thanks!

  23. Not the answer you are looking for?
    Search for more explanations.

    • Attachments:

Ask your own question

Ask a Question
Find more explanations on OpenStudy

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.