A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

anonymous

  • one year ago

Find the angle between the given vectors to the nearest tenth of a degree. u = <-5, -4>, v = <-4, -3>

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

    Hi! I can help you! :)

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

    Do you have any ideas about how to get started, or are you completely stuck? :)

  3. johnweldon1993
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Hint...dot product \[\large \vec{u} \cdot \vec{v} = ||u|||v|| \cos(\theta)\] So \[\large cos(\theta) = \frac{\vec{u} \cdot \vec{v}}{||u|| ||v||}\]

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

    @BasketWeave completely stuck :-(

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

    Okay, no problem! John's given you a clue here: we can use the dot product.

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

    Do you know how to find the dot product between two vectors? :)

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

    u * v = <-5,-4> , <-4,-3> =-5(-4) + -4(-3) = 20 + 12 = 32 |u| = √(-5)^2 + (-4)^2 =√25 +16 = √41

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

    |v| = √(-4)^2 + (-3)^2 = √16 + 9 = √25 = 5

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

    u * v = 32 |u| =√41 |v| = 5

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

    \[\frac{ 32 }{ \sqrt{41}5} \]

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

    Well done :) Carry on...

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

    im getting 0.02648....

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

    i calculated wrong

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

    now i got, 0.99951.. one of my answer choices is 0.9 degrees, is that correct?

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

    Well, try and remember what that 0.99951 means... :) It's not actually the angle!

  16. johnweldon1993
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Right, that leaves us with \[\large cos(\theta) = 0.99951\] What do you get when you actually solve for the angle?

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

    1.8 degrees?

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

    Excellent, well done!

  19. johnweldon1993
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Correct indeed

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

    thank you guys so much for your help!

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

    You're most welcome :)

  22. 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.